Abstract:Abstract:This paper probes into the phenomenon of the “double occurrence” of the accusative case marker “ヲ” in a simple sentence in Japanese. By exploring the syntactic feature and semantic function of the noun phrases containing morphological case “ヲ” , the event structural features and semantic driver for the double occurrence of “ヲ” are clarified. The investigation reveals that the double-wo in one sentence marks different levels of semantic relations respectively. The assignment of accusative case marker to motion-action relation manifests the pragmatic function of the event causality . The mechanism of the assigning of Japanese accusative case marker provides a new research perspective for the study of the restraining factors of assigning case marker in general linguistics.