Abstract: The results of cotton field experiment with membrane coverage show that coverage with narrow or wide membrane increases cotton yield by 46．8％ and 5 1．3％ ．and improves the germination rate and cotton growth．Changes of soil temperature during all seasons show that during the early period(from the last ten days of April to June)，the accumulated temperature of soil under narrow or wide membrane coverage increases 105℃ and 195℃ compared with uncovered respectively，and soil temperature increases 0．7～3．2℃ ，but this heat effects reduce during the later period．Coverage increases soil temperature of all layers，and temperature increments decrease along with increasing of soil depth．The temperature from morning to night has no obvious difference between coverage and uncovered at the early stage，but at the later stage (from July)compared with uncovered，the temperature under coverage decreases by 0．8～ 4．2℃ ．The temperature effect with wide membrane is more effective than that with narrow membrane．