To evaluate performance of flashing light, a new system is made for intensity detection of flashing lights in this paper, which uses labview platform. Not only the flashing waveform in a certain period of time can be observed, but also can exactly calculate peak intensity, efficient intensity，flashing frequency and flashing time in a high-speed. We introduced the parameter calculate principle, hardware configuration and labview program design, a effectual method was proposed to resolve the problem of data losed easily in data acquisition process，and data can be store. The operation easily and any flashing waveform can be detected which flshing time greater then 0.1s, the acquisition maximum time can reach 10s. A batter evaluation of flashing light performance can be made by this system.