Abstract: Because of the special nature of its meaning，possibility complement makes a difficult point for foreign students.According to the statistical data from the compositions of Thai students，we have a conclusion that the acquisition of possibility complement takes longer time than result complement and directional complement，and shorter than quantity complement and degree complement.Compared with the acquisition of prepositional phrases as complements，the students perform better in their acquisition of the possibility complement in the primary stage than they do in the intermediate and advanced stage.The major error types and learning difficulties are disclosed through the statistical analysis of compositions and the questionnaires；then we give the causes on the basis of the comparison between Thai language and Chinese and propose some teaching strategies.

Key words: Thai students, Chinese, possibility complement, acquisition, negative transfer