Objectives: This study investigated deficits of prospective memory in patients with alcohol use disorder (AUD) using the event-based and time-based prospective memory tasks. Methods: Twenty-eight male AUD patients and 25 normal controls participated in this study. In the event-based prospective memory task, participants were required to respond when the pictures were presented in red square. In the time-based prospective memory task, participants were required to respond every 30 seconds from the beginning of the task. As a control task, semantic classification task was administered. Results: The AUD group exhibited significantly lower accuracy rates and longer response times than did the control group in both event-based and time-based prospective memory tasks. Additionally, performances on the time-based prospective memory task were significantly worse than those on the event-based prospective memory task for AUD group. The two groups did not exhibit significant differences in semantic classification task. Conclusions: These results indicate that patients with AUD have deficits in prospective memory, and time-based prospective memory is more impaired than event-based prospective memory in these patients. These results further indicate that event-based prospective memory and time-based prospective memory require different cognitive functions and may have different neural mechanisms.