In order to improve the factory inspection ability of compound fertilizer production enterprises around Beijingof China and improve the quality of compound fertilizer products，the proficiency testing of determination of availablephosphorus content for compound fertilizer is carriedout.18 enterprises participate in the proficiency testing，samplesused for proficiency testing are passed the homogeneity analysis and stabilityanalysis，the methods of frequency distribution statistics and robust statistics“Z-score”are used to analyse the results of available phosphoruscontent.It is shown that theresults of available phosphorus content are concentrated in the vicinity of the median value17.08，with no obviousdeviation，and the distribution approximates normal distribution.The | Z | of the results are less than2，and the satisfactory rate is100%.The results show that the laboratories of 18 certified enterprises can meet the requirements of GB/T 8573-2010 forthe determination of available phosphorus content for compound fertilizers.The overall level of laboratory detection ability of available phosphorus content for compound fertilizers is satisfactory in certified enterprises of compound fertilizer around Beijing of China.