Abstract: Abstract: In order to guide the agricultural product processing industry in Hebei Province specifically in the high-quality and fast development track, we analyze the applicable conditions of the Deng's grey incidence model based on the Chinese scholar Deng Julong's grey system theory. When studying the correlation of behavior index sequence whose data order can be changed, we put forward the improved method by using interval value quantization algorithm instead of initial value or average value quantization algorithm, and using the data 1 and 0 instead of the absolute difference between maximum and minimum value. This can not only solve the problem of different results due to the change of starting point data sequence and reference sequence, but can also solve the problem of destroying the intrinsic relationship of data by dimensionless processing. In order to reflect the certain sector's impact on national economy and based on the input-output theory, this paper builds the forward and backward virtual optimal reference sequence and studies the correlation effect among this sector and others. The data come from the input-output tables of 139 sectors of Hebei Province in 2012 and other agricultural product processing industry statistical data from 2013 to 2016. According to the national economy industry classification standard and research needs, based on Hirschman industry relevancy criteria, Rostow industrial diffusion effect criteria and Ricardo's comparative advantage criteria, 17 categories of agricultural processing sectors are selected as the research objects, and 8 evaluation indices have been determined, including influence coefficient, response coefficient, main business income ratio, proportion of exports and domestic selling outside the province, economic benefit coefficient, economic growth rate, economic technology coefficient and the structure of the labor input coefficient. The high correlation coefficients such as economic benefit coefficient, economic technology coefficient and the structure of the labor input coefficient are processed based on the improved grey correlation analysis method and calculation of 8 categories of correlation indices. Then the optimization analysis on the influence coefficient and response coefficient is performed. Finally, 6 evaluation indices are determined to evaluate the 17 categories of agricultural processing sectors comprehensively. The results show that the comprehensive evaluation of the fur feather silk industry is the best, with main business income at the 1st place, and the total of exports and domestic selling outside Hebei Province at the 2nd place. The economic benefit coefficient, response coefficient and economic growth rate of this industry are all in the top 5. The comprehensive evaluation of cotton and jute products industry is at the 2nd place. Same as fur feather silk industry, it becomes the key part of business main income and export products of agricultural processing in Hebei Province. The Chinese medicine processing industry ranks the 4th with excellent economic growth rate and economic benefit. This result meets the strategic deployment of revitalizing the traditional Chinese medicine career and developing the Chinese medicine characteristic industry. The comprehensive evaluation of dairy products industry is at the 5th place with response coefficient, export or outflow outside province domestically and economic growth rate at the 5th, 6th and 2nd place respectively. This industry develops well. The comprehensive evaluation of grain and plant oil processing industry ranks the 6th and 7th respectively, which indicates large capacity of grain and oil production in Hebei Province. It has a good effect on the national economy and increases the income of main business. The fruits and vegetables processing industry ranks the 8th with 9.4% of the average annual main business revenue growth, which reflects the obvious effect on agriculture transformation and upgrading in Hebei Province as the second largest vegetable production province in China. The comprehensive evaluation of rubber manufacturing industry ranks the 9th with economic benefit, growth rate and main business income all at the 6th or 7th. It is concluded that the 5 edible agricultural processing industries and 3 traditional processing industries have high competitive advantages and should be supported as the leading industries. Although the comprehensive evaluation of the sugar industry is better, it is too small to be the leading industry. This paper makes innovation in correlation analysis method and provides an important reference to the agricultural processing industry improvement in Hebei Province.