||The present study attempts to investigate the syntactic and semantic properties of the final particles - 'LEI', 'ZYU' and 'LAA' in Hong Kong Cantonese, with the primary focus on the aspectual meanings expressed by them. It is noted in the linguistics literature that 'LEI' expresses past time, assertion, emphasis, etc., whereas 'ZYU' and 'LAA' are related to the meanings of temporariness and a change of state. The present study will show that 'LEI', 'ZYU' and 'LAA' form an aspectual system, namely, a perfective-imperfective dichotomy. While 'LEI' conveys the perfective aspect, 'ZYU' and 'LAA' mark the imperfective aspect. Being a perfective marker, 'LEI' indicates the completion of a situation with the further emphasis that the situation discontinues at the reference time. On the other hand, both 'ZYU' and 'LAA' are associated with the expression of the imperfective aspect with inchoative aspect. 'ZYU' presents the continuous state of a situation with an expectation that the situation will come to an end sooner or later, whereas 'LAA' indicates the anticipation of the coming about of a new situation, or emphasizes a change of state, or both. The proposal made in this study not only can account for the syntactic and semantic properties exhibited by 'LEI', 'ZYU' and 'LAA', but also can partly explain the differences in use between these three aspectual particles and a number of related aspectual verb suffixes. The differences exemplified by 'LEI', 'ZYU' and 'LAA' on the one hand, and the related aspectual verb suffixes on the other hand, further suggest that Cantonese has a rich inventory of grammatical elements to present a situation in numerous ways, according to the viewpoint of the speaker.