Sanitary and Phytosanitary (SPS) measures are the most applied and most influential nontariff barriers in the agricultural trade. An accurate estimation of the trade protection effect of SPS measures can provide a basis for both the adjustment of agricultural product export tactics and the negotiation on free trade zone agreements. This paper uses a partial equilibrium model and the System Generalized Moment Method (GMM) to estimate the effects of SPS measures on the quantities of agricultural import,based on the HS 2digit coded agricultural product trade data from 37 countries,including OECD and China,from 2001 to 2018. Then the quantity effects of SPS measures were converted into price effects,and the advalorem equivalents（AVE）was estimated on the basis of calculating the import demand elasticity of agricultural import in each category. It is found that the AVEs of SPS measures for agricultural products in this sample ranged from 4.6% to 60.6%,with an average of 21.07%,which was twice the weighted average nominal tariff. From the perspective of processing levels,the average AVE of SPS measures for primary agricultural products was 60% higher than that of the processed. Among them,the AVE of live animals,which had the highest risk of epidemic diseases,was 60.6%. Therefore,exporters should comprehensively consider both the nominal tariff and the AVEs of SPS measures when choosing the target markets.