Abstract: In this paper, the photometric accuracies of 280 mm whole sky area rotatable photoelectric array which sited in Jilin astronomical observation are studied. A set of photometric standard stars of M67 open star cluster are observed.Firstly, we preprocess the image in IRAF(Image Reduction and Analysis Facility) and the photometry data is acquired by using the method of differential photometry. Then, the data is extracted for least square linear fitting, the fitting results show the main extinction coefficient and the transformation equations from instrument magnitude to standard magnitude. Finally, the root mean square error between transformed magnitude and standard magnitude is calculated to evaluate the photometric accuracy of the equipment. Our results indicate that the photometric precisions of this equipment is 0.13 mag for objects brighter than 13.8 mag under photometric conditions.In order to check this result we match the image with UCAC2 star catalogue and calculated the photometric accuracy. The results are basically similar to the former. The photometry accuracy of this equipment can basically meet the requirements of space debris observation.