This study aims to compare and analyze the use of refusal speech act strategies by Korean native speakers and Chinese learners of Korean, and to reveal the similarities and differences between the two groups. 94 Korean native speakers (KK) and 135 Chinese Korean learners (CC) completed a questionnaire using the Discourse Completion Test. T-tests results showed that, KK's speech strategies are more influenced by social factors. CC tend to use assertion and lack of ability strategies, while KK prefer to use strategies to promise the future, express desires to accept, show sympathy, and adjust flexibly according to social changes. Therefore, CC's refusal speech is more direct, while KK's refusal speech is more polite. Through post-event interviews, it was also discovered that Chinese learners of Korean encounter problems in implementing speech acts, such as insufficient understanding of complimentary expression and strategy, neglecting conversational variables, interference from the native language and cultural differences.