Abstract: Abstract: Potato (Solanum tuberosum L.) is one of the four major crops in the world, after rice, corn (maize) and soybean. In order to meet the increase in demand, its planting area is increasing worldwide. Being no exception, Heilongjiang Province in the Northeast part of the P. R. of China also expanded the potato planting area with 262 thousands hectares by the year of 2015. However average yield in the province was lower than the national average level with only 41 220 kg/hm2, because of the factors, such as backward cultivation technologies, irregular planting system, and unreasonable climate conditions. Among them, soil condition affected by cultivation was a fundamental factor for improvement of potato yield and potato tuber rate. As the cultivating soil machinery developed slowly, soil conditions cannot reach the ideal level, which create issues including seedlings seriously injured by mechanical operation pressure, increased green potato rate, low commodity potato rate, and hence farmers' income cannot keep the same pace with the potato planting area increasing. A special-designed ridging cultivator was developed (Patent No.: ZL 201220010382.2) to solve the problems. The cultivator is 4 m long for plough horizontal frame, with five plowshares fixed on the plough frame through quadrilateral spindle. The plough shape is the most special part, as its curved surface is beneficial to create a full ridge. In the paper, a comparative field tests were carried out by using the cultivator and a traditional cultivation soil plow (machine type: 3Z-2A). In the field tests, four ridge spacing with 65, 70, 80 and 90 cm were set by using the cultivator respectively. The cultivator was operated twice during the period from seeding to budding. The results showed that after operation by the cultivator, soil weight of ridge body was increased with 21.7% to 33.4% as much as that of the control (CK). Potato in the treatment applied the cultivator was beneficial for plant growth, main stem prolongation and dry matter accumulation during growth period, meanwhile potato stolon numbers multiplied, and dry matter accumulation weight of potato in the ridge body increased with 4.8 to 5.4 g in the first year, and 4.2 to 4.5 g per plant in the second year. The dry matter accumulation weight changed largely with the ridge spacing increasing, the increasing range was from 11.1% to 23.8% compared with the control (CK). Regarding the dry matter mass underground, the results showed that treatment with 80 cm ridge got the highest with 4.95g per plant as an average value for two years. In addition, the special-designed ridging cultivator not only increased the potato tuber yield, but also kept the potato tuber size uniform. It increased the proportion of large and middle size potato tubers and decreased the proportion of small potato tubers. The average potato yield for two years was increased from 38 215.0 to 43 131.2 kg/hm2, 1.1% to 7.3% higher than that of the control (CK). Commercial potato yield for two years was averagely from 33 788.9 to 39 346.7 kg/hm2, 4.1%-11.2% higher than that of the control (CK), and the green potato tubers yield for two year averaged from 670.7 to 834.3 kg/hm2, 18.7% to 28.8% lower than that of the control (CK). Among all treatments with different ridge spacing, the potato yield with 80 cm ridge spacing was the highest with 43 131.2 kg/hm2 and green potato rate was the lowest with the yield of 670.7 kg/hm2. In the study, 80 cm ridge spacing was recommended when operating the cultivator, as a result it could offer new direction for potato production.