Abstract: With the continuous development of industry, environment pollution such as soil acidification and heavy metal pollution of soil becomes increasingly serious, especially in the acidic soil region of southern China. Liming is a traditional and effective method to improve acidic soil. Manual spreading is a kind of traditional method of liming, but it is inefficient and has some side effects like skin damage of workers because of the corrosive property of lime. In order to solve the deficiencies of manual liming and compensate the technology gap of liming machine between domestic and overseas market, we designed a lime spreading machine which was able to be assembled with other agricultural machinery to become combined machine. The development of liming machine has great significance to improve liming efficiency and working conditions. This paper discussed the structure and working principle of the pros spiral lime spreading machine. The machine used the spread roller which was similar to the structure of pros spiral as working parts, used the overlapped waist-shaped hole as the lime spreading outlet, and controlled the waist-shaped hole overlapping area through adjusting assembly to adjust the lime spreading amount. Through experiment we determined the lime outlet size and the lime spreading roller's rotation speed of the lime spreading machine, and experiment results showed that: Firstly, when the lime spreading roller speed was below 125 turn per minute, for the same waist-shaped lime spreading outlet, the lime spreading amount per turn of lime spreading roller could be treated as a constant value, i.e. the spreading amount and lime spread roller's rotation speed were in a linear relationship; Secondly, when the number of lime spreading plate was 40, the hole was waist-shaped hole with the size of 25 mm×10 mm and the rotation speed of the roller was in 120 turn per minute, we got the lime spreading amount of 1 500 kg/h which met the maximum requirements of lime spreading. Considering the linear relationship between the lime spreading amount and the number of lime spreading hole, and the complex conditions after assembled with rotary cultivator, we increased the number of the waist-shaped hole and decreased the rotation speed of lime spreading roller meanwhile kept the lime spreading speed unchanged, and at last determined the lime spreading hole number to be 60 and the roller's rotation speed to be 80 turn per minute as the optimal scheme. We also analyzed the power consumption condition of the lime spreading process and calculated the total power consumption of the working process. Finally, the field test of the lime spreader was carried out, which was conducted in the dry paddy field. Field test results showed that, under the conditions of the lime spreading cultivator at a speed of 5 km per hour, the lime spreading roller at a speed of 80 turn per minute and the overlapping area of the lime spreading hole at maximum size, when the adjusting bar of adjusting mechanism was located in Location XIII, the lime spreading amount reached 1 566.7 kg per hectare. When the adjusting bar of adjusting mechanism were located in Location XII, X and VII, respectively, the lime spreading amounts met the demands of annual lime spreading amount for the first, second and third year, respectively; and when the adjusting bar was at Location II, lime spreading machine almost closed all the lime spreading holes.