Abstract: In order to meet the test requirement of large sensor area light screen indoors, detection sensitivity of a lens-style light screen which is composed of arc light source and sky screen target was analyzed. The composition of this lens-style light screen test system was introduced, the working mechanism of its fan screen was analyzed, and the calculation formulation was put forward. According to the lens imaging principle and the fan screen forming principle, the influence of the light source placed distance R and the lens objective distance l on the detection sensitivity was researched theoretically, and the verified experiment was conducted. The results show that the mentioned lens-style light screen can work normally, its sensitivity is higher than the conventional sky screen target, the experiment results can provide reference for further engineering design.