In the process of agricultural production，available phosphorus determination of cropland soil and fertilizer is necessary for formula fertilization protocol establishment. The accuracy of detection methods is important for judging the quality of fertilizer and realizing formula fertilization. In this study，the sensitivity and accuracy of inductively coupled plasma emission spectrometry(ICP-OES)and vanadium molybdenum yellow colorimetric methods were compared on available phosphorus determination，it was found that the determination limit of ICP-OES method was 0.05 mg/L at 213.6 nm wavelength，while it was 0.32 mg/L for the vanadium molybdenum yellow colorimetric method at 400 nm. The detection accuracy of the two methods was compared. It showed that the accuracy of ICP-OES method was not affected by phosphorus concentration as the determination accuracy of different phosphorus concentration standard samples was higher than 96%. However，the accuracy of traditional vanadium molybdenum yellow colorimetric method was greatly affected by phosphorus concentration and detection wavelength，as detection accuracy was greatly reduced for samples with phosphorus concentration less than 5 mg/L，and the accuracy was lower than that of ICP-OES method. Based on the results，400 nm detection wavelength was a ideal condition for vanadium molybdenum yellow colorimetric method for phosphorus determination of unknown samples.