Abstract: Tomato variety (inbreed lines) with different low light-resistant ability had different responses against light. So the confirmation of appraising indicator of low light tolerance were helpful to filter low light-resistant tomato variety (inbreed lines) fleetly from the abundant germplasm resources and elevate selection efficiency. 4 Tomato variety (inbreed lines) with different low light-resistant ability were treated by shading after planting. The changing of photosynthetic characteristics and economic trait were studied. Correlation analysis and Path analysis of 11 characters were carried out also. The results show that the indexes such as net photosynthetic rate, Stomatal conductance, transpiration rate, fruit set percentage, per-fruit weight and yield of single plant dropped at different extents. The direct path coefficient that fruit set percentage, net photosynthetic rate, CO2 concentration between cell to yield of single plant under low light environment were 1.92, 1.76, 2.13 respectively, and Correlation coefficient were 0.53, -0.09, 0.48, respectively. It was suggested that fruit set percentage under low light environment might be used as the believable indicator to identify the low light tolerance of tomato, and net photosynthetic rate, CO2 concentration between cell under could be used as a assistant indicator.