Abstract:The present study, by conducting two experiments, i.e., semantic match judgment task and picture description judgment task, attempts to investigate issues concerning accessibility of the mapping and projection principles and related feature reassembling among second language learners of different proficiency in the process of second language acquisition (SLA), focusing upon the conversion from predicate to phrase structures.The results were as follows, 1) The projection principle and mapping principle are proved to be directly accessible in the early stage of SLA and in the whole process of SLA; Thus, the acquisition is constrained by the relevant principles.2) The progress of the concerning acquisition process is constrained by the acquisition sequence of the single feature and the reassembling of the complex features, and all these features can be fully acquired; Thus, the present study gives support to the hypothesis of the feature assembling.