Abstract: Since the detection range is one of the core indexes for practical application of near ultraviolet detection system, the study of detection range has great practical significance. This paper expounds the principle of near ultraviolet detection system and builds the near ultraviolet detecting range model based on the signal to noise ratio(SNR) analysis of photoelectric detection system. In addition, it analyzes some effects on detection range in detail, including the radiation characteristics in the near ultraviolet spectrum and atmospheric transmittance. Finally, it gives an example using the existing near ultraviolet detector in lab in studying the detection range based on the established model. The study can provide effective theoretical guidance for the development and deep research in the field of near ultraviolet detection technology.