The purpose of this study is to identify and understand the impact and constraints of implementing ERP-based PDT in accounting information system of inventory and its impact in enhancing firm performance. The research was conducted in PT Matahari Department Store Tbk. Trancedental phenomenology was employed in this study to analyze qualitative data. The authors interviewed 3 informants, namely expedition supervisor, area supervisor and sales associate. The findings of the study reveal that, first, ERP-based PDT implementation on inventory information systems had a positive impact. There was an increase in performance, particularly in the process of receiving incoming goods and carrying out stock opname. In addition, PDT implementation constraints are quite small, that is the PDT synchronization problem for ERP program database servers. This problem occurs when the wifi signal is less stable. This study has important implication, the company can find out the impact and constraints of PDT implementation in enhancing their performance. Keywords: inventory, PDT, ERP, accounting information system, trancedental phenomenology