Abstract: By comparing effects of three different planting modes on the yield of spring-sown potatoes in Northwest China，results showed that yield of spring-sown potatoes under straw mulching increased by 10%~20% compared with that without mulching，and yield increased significantly （P<0.05）；compared with that under plastic mulching，yield of potatoes under straw mulching was not significant（P<0.05）.Therefore，straw mulching could achieve high yield and increase income of potato cultivation in Northwest China.Main reason was that straw mulching could effectively regulate physical and chemical characteristics of soil.In most areas of arid and water-deficient northwest China，it could effectively improve water use efficiency，which was key factor to ensure increase of potato production.In order to provide theoretical basis for spring planting of potato straw mulching in Northwest China，main reasons of increasing potato yield by straw mulching were summarized.