The inorganic fertilizer，organic-inorganic compound fertilizer and organic fertilizer were pretreated by microwave wetting digestion，and 3 kinds of heavy metals，namely cadmium，lead and chromium，in the digesting aqua of the fertilizers were analyzed by the flames atomic absorption spectrophotometry.The methods were convenient，efficient，accurate and sensitive，and the detection results were stable and reliable.The results showed that the relative standard deviations of cadmium when repeated for 7 times were 1.86%，0.31%，0.29% for low，medium，and high concentrations，while those of lead and chromium were 3.84%，1.36%，0.70% and 4.36%，0.59%，0.39%，respectively.The recovery of the cadmium was 81.7%-99.2%，the recovery of the lead was 88.7%-97.8%，and the recovery of the chromium was 87.1%-99.4%，and all of which had a good recovery rate.The limits of detection of cadmium，lead and chromium were low.The correlation coefficients of the standard curves for chromium in its mass concentration range were above 0.99740.