When energy dispersive X-ray fluorescence (EDXRF) spectroscopy is used to analyze low-content element in samples with complicated background, interference from X-ray scattering will affect system detection precision, and X-ray scattering is closely related to X-ray beam spot intensity. A shimmer image intensifier is utilized to collect projection image of X-ray beam spot under different working current and the intensity of mixed and scattered ray around the projection flare is used to characterize X-ray scattering intensity, two methods to reduce X-ray beam spot intensity, i.e. reducing X-ray tube current and collimator diameter, are obtained so as to reduce the impact of the mixed and scattered ray on X-ray. It is found that when the EDXRF method is used to analyze low-content element in samples, the method of reducing collimator diameter is more effective than the method of reducing X-ray tube current for decrease of X-ray scattering, and the system detection precision can be improved when the collimator diameter is reduced and the X-ray tube current is increased meanwhile. The experimental results show that for detecting microelement Cr in the soil, actual relative error of this method is 0.9%~6.6%, and relative standard deviation is 0.7%~1.5%. p is higher than 0.05 in t test, and the test result has no significant difference with standard samples statistically.