The effect of black film mulching on potato nutrient,yield as well as soil quality is studied in Nanjing,with potato variety of Helan No.7 as test material.Three treatments were designed during potato growth,including ridges mulched with black plastic film (BM),ridges mulched with commonly used white film (WM),and non-mulched (CK) flatland as control.The results show that the black film mulching significantly increases the tuber starch content and potato yield,and changes soil quality as well.The potato yield of BM treatment is 31.1% and 43.7% higher than that of WM and CK,respectively.The content of available potassium in topsoil is lower in the two film mulching treatments;the content of available phosphorus is lowest,while the ammonium nitrogen and nitrate nitrogen are highest in deep soil in BM treatment.The mulching treatment,especially with black film,improves soil environment such as topsoil water content and temperature,which favors the growth of miniature potato.