This research deals with Antecedent Connected Deletion(ACD) phenomena in English. To understand the ACD reconstruction, this research is based on Chomsky’s(2005) assertion that cognitive system is the third language design factor(i.e. data processing and computational efficiency). This research introduces Optimality Approach to discuss the connection between the ACD reconstruction and the cognitive system. The researcher quotes two example sentences from Lee’s(2023) study. In each sentence, there is an ACD construction. To extract ACD reconstruction candidates, the researcher sets up a Grammar Model: Surface Structure(generation of ACD), Predicate Structure(Predication of ACD) and Logical Form(Parallelism of ACD). On the Grammar Model, the researcher deduces several ACD Reconstruction Candidates. For evaluating the Candidates(to choose Optimal Candidate), the researcher applies some Constraints. The Constraints are *AMBIGUITY(No Ambiguity), PREDICATION, and PARALLELISM. The research shows that, in English, there is a ranking system for choosing Optimal ACD reconstruction: *AMBIGUITY >> PARALLELISM >> PREDICATION. This research argues that the ranking system is connected with the cognitive system: avoiding ambiguity and focusing on the relations between two propositions. The argument related with the ACD reconstruction and the cognitive system could be connected with English education in terms of the possibility that studying English speakers’ cognitive system could be a useful resource for English teaching. Optimality Approach could be the first step for the studies.