Abstract: In order to reduce the use of chemicals in greenhouse vegetable,in this study,two treatments of release Nesidiocoris tenuis（treatment A:release Nesidiocoris tenuis during tomato first fruiting stage,treatment B:release Nesidiocoris tenuis during tomato fourth fruiting stage）and the control without releasing Nesidiocoris tenuis at the corresponding period were set up.The control efficacy of Nesidiocoris tenuis on the greenhouse whitefly was calculated by investigating the number and changing trend of the greenhouse whitefly and Nesidiocoris tenuis,and the biological control technology of the greenhouse whitefly in the greenhouse was further explored.The results showed that the highest number of Nesidiocoris tenuis during tomato first fruiting stage and fourth fruiting stage was 21.67 and 31.33 per 100 leaves.The highest number of greenhouse whitefly during tomato first fruiting stage and fourth fruiting stage was respectively 2 333.0 and 2 725.0 per 100 leaves in the control area,the lowest number of greenhouse whitefly was respectively 227.3 and 404.0 per 100 leaves in the treatment area,and the control efficacy cpild maximize to 90.3% and 84.1% respectively.The control efficacy of releaing Nesidiocoris tenuis during tomato first fruiting stage was slightly higher than that during tomato heading and fourth fruiting stage.As a consequence,it is feasible to control the greenhouse whitefly by applying Nesidiocoris tenuis.