Soil available P,K and N were determined by both ASI and China routine methods.Results showed that:(1) ASI-P was significant positively correlated with Olsen-P,the correlation co-efficient was respectively higher in paddy soils and acid soils than in upland and neutral or alkalic soils.(2) ASI-K was significant positively correlated with NH4OAc-K,and the correlation co-efficient was respectively higher in upland and neutral or alkalic soils than in paddy soils and acid soils.(3) ASI-N was much lower than alkaline hydrolysis nitrogen.The correlation co-efficient between them was relatively higher in paddy and acid or neutral soils.