This study examined the acquisition of Korean stop sounds /t/(ㄷ), /t’/(ㄸ) and /th /(ㅌ) by Chinese learners of Korean using Event-related potentials (ERP). Fifteen advanced learners and ten intermediate learners participated in both a behavioural and an ERP experiment. The intermediate learners were significantly less accurate than the advanced learners in discriminating /t’/ from /t/. The overall ERP result also showed less sensitivity of the intermediate learners compared to the advanced learners to the distinction between different stop sounds. The results indicate that the phonemic acquisition of Korean stop sounds by L2 learners develops as the learners’ proficiency increases