Traditional haze detector haze when calculating the concentration in the air only consider the scattering of light suspended solids, without considering the effects of humidity on haze concentration. Aiming at the shortcomings of traditional haze detector, this paper presents an algorithm that contains concentrations of haze and humidity parameters amendment, designed to complete the haze detection system. To reduce the impact of environmental factors, haze detection system uses a closed optical system and a constant optical power control and designs the optical transmitter module, optical receiver module, temperature and humidity control module, control module, air sampling and optical module, monitors components. By experimentally measured concentrations and haze linear relationship between the intensity of the scattered light using aerosol generator, the linear correlation coefficient is 0.976 5. By detecting the concentration of PM2.5 in the atmosphere, finally proves that the haze detector can work effectively.