According to toxic response factor of different forms of heavy metals, rational application rate of sewage sludge compost was determined. Pollution index and geoaccumulation index were used to evaluate contamination degree of sewage sludge compost. Rational application rate of sewage sludge compost in Yangling was 3.69t/(hm2?a). This method stressed the importance of the forms of heavy metals and made up for the shortage of only controlling the total amount of heavy metals in the past. Results showed Cd was the most important element to restrict application of sewage sludge compost in this area.