Abstract: In this study， we investigated the impact of different microclimatic factors in greenhouse with new or old films on yield and quality of cherry tomato cultivar Qianxi. The differences in temperature， humidity and solar radiation in the condition of thermal insulation of greenhouse in winter and spring and wholeday ventilation in spring and summer， with new greenhouse film or old one， were observed and analyzed. The growth periods of cherry tomato were recorded and yield and quality were measured. In the whole growth period， the daily average temperature in greenhouse with new greenhouse film or old one was about 3 ℃ higher than the outside with no significant difference. The condition of thermal insulation of greenhouse with new greenhouse film was better than the old one during the daytime of sunny days in the airtight condition in winter and spring. There was no significant difference in the condition of thermal insulation of greenhouse with new greenhouse film or old one in the other periods， no matter it was sunny or rainy， the shed was open or closed. The average humidity of greenhouse with old greenhouse film was 3.6% less than that with new one regardless of season or greenhouse ventilation， which played a role in preventing disease and high humidity. The average illumination in the greenhouse with new greenhouse film was 20.6% higher than that with old one. The flowering and fruit mature period of cherry tomato was 35 days earlier than usual in the greenhouse with new greenhouse film. The fruit size and the quantity of diseased fruits in greenhouse with new greenhouse film or old one differed significantly. However， the single fruit weight， sugar content and yield showed no significant difference.

Key words: greenhouse film, microclimatic factors, cherry tomato, yield, fruit quality