This study conducts an empirical analysis of the diachronic development of space-category adpositions, allowing for a reevaluation of the linguistic status of Chinese complements. Although Archaic Chinese initially showed a mixture of languages from the Yin(殷) and Zhou(周) dynasties, its fundamental SVO structure was consistently preserved. The common use of the adpositional phrase "於" in Archaic Chinese, regardless of thematic roles, following the predicate verb, aligns precisely with the universal word order for adverbials. Therefore, recognizing all post-verbal positions in Chinese as complements warrants reconsideration. However, the subsequent development of adpositional phrases, which began to appear both before and after the predicate verb, deviated from the universal word order. This unusual development can be attributed to the complete establishment of Chinese as an isolating language and the influence of PTS. The alignment in timing between the emergence of new adpositions, originating from verbs and evolving into adpositions, provides further insight. Newly emerged adpositions, still in the process of establishing their status, adhered to the PTS order of verbs. As these adpositions solidified their status, their syntactic positions began to differentiate before and after the predicate, depending on thematic roles. Previous research has mainly discussed the development of Chinese adpositions, focusing on a limited set of adpositions and language data. In contrast, this study offers a comprehensive review of the diachronic development of spatial adpositions and examines the establishment of syntactic positions for Chinese adverbial adpositional phrases. Additionally, this research provides a new perspective on the linguistic status of Chinese complements, paving the way for further studies in this area.