Standard substance with certificate were regularly applied to demonstrate the veracity of test data to improve the accuracy and observe the influences of operator，apparent，material and environment which lead to the phenomenon of beyond limitation.Quality control of effective phosphate in soil assay with national standard soil was a simple and practicable method to ensure the reliability of the data.The test results showed that，except the data collected at 27 04 2010 which was not stable，other data were all between 164~198 mg/kg.The relative standard deviation was 620%.There were 93% of test points were between two auxiliary lines and no seven consecutive points were at the same side of mean line in quality control chart.So the quality control chart was reliable.Comparing with the results of similar period in 2010，the content of effective phosphate in soil was higher in 2011.Most of the data in 2011 were above 183 mg/kg and the accuracy of the data also was higher than that in 2010.