Abstract: In order to explore the feasibility of ion exchange resin membrane (IERM) as a nutrients-extracting tool in the study of ammonium and potassium ions interaction in soil and the relation to canola nutrients uptake, the IERM incubation and pot experiments were conducted on the soils with such exactly similar conditions, as moisture, temperature, et al. The results showed that the amount of ammonium extracted by IERM was reduced by the co-existing of potassium, but that of K+ extracted was not influenced by ammonium co-application, which was concerned with the preferential fixation of ammonium in soil when co-applied with potassium. The significant correlation was detected between the nutrients amount extracted by IERM with plant nutrients uptake and dry matter weight, which demonstrated the feasibility of IERM as a ‘roots simulator’ in the study of nutrients interaction in soil. However, IERM was not plant roots, resulting in some inconsistency in the change of nutrients extracted by IERM or by canola, which was seldom mentioned in the previous studies. The existence of such inconsistency implied that more efforts should be taken on the study of IERM application conditions, in order to make the best use of IERM in the study of the influence on plant nutrients uptake by ammonium and potassium interaction in soil.