Abstract: This paper is based on the follewing works: systematical studies by the auther on the theory of land quality evaluation at home and abroad,works of land guality evaluation in yuisu county of Jilin provinle and suming up the experince of 12 counties in land quality evaluation, The paper studies and researches several important problems in land quality evaluation, such as, the basic concepts of land quality evaluation, differentiation of land evaluoition unit , determination of evaluation factors and indexes, the theory and method of grading land quality by using the regression analysis with the soil speries regarded as statistic units. The research results have been used in land quality evaluation of county level and a significant efficiency has been gained.