As the cooperation in multiple tasks between employees is increasingly necessary for companies in today's dynamic business environment, facilitating helping behaviors among employees becomes a critical issue for managers. However, employees might have no time to help their colleagues other than striving to meet the deadlines themselves. To address this problem, we introduced temporal leadership--which could effectively allocate and utilize the time resources of employees--as an antecedent of employee's helping behavior. Then we developed a theoretical model based on the effective event theory and the person-situation interaction perspective to explain the impact mechanism of temporal leadership on helping behavior. After that, we examined our hypotheses by using a sample of 260 employees from three provinces in South China. By implementing path analysis via a procedure of boostrapping with Mplus 6.10, our analyses indicated that: (1) temporal leadership positively predicted employee's helping behavior; (2) both harmonious passion and obsessive passion simultaneously played the role of mediator in the relationship between temporal leadership and helping behavior in our multiple mediation model, and the specific mediating effect of harmonious passion was relatively stronger; (3) proactive personality moderated the relationship between temporal leadership and helping behavior, so that the direct and total effect of temporal leadership on helping behavior were both stronger for the employees with lower level of proactive personality. This study contributed to extant literature in three ways. Firstly, by introducing temporal leadership, it could not only justify the theoretical value of this construct, but also broaden our understanding on the antecedents of helping behavior. Secondly, this study could give more details about why as well as how temporal leadership was able to facilitate helping behavior by integrating the multiple mediations of two types of passion and the moderation of proactive personality simultaneously, and it could also push forward the researches on temporal leadership in a sophisticated way. Finally, our analyses might also shed light on the theoretical applicability and revision of effective event theory as well as person-situation interaction perspective. In terms of practical implications, leaders should learn how to manage employees' time effectively, such as appropriately reminding members of deadlines, planning the schedules for employees, coordinating the pacing of tasks were implemented, etc. In this way, it might be easier for employees to make time to help others. Secondly, while managing the time of their subordinates, managers should show their care about employees' time-related well-being, rather than the accomplishment of work. This might be helpful in motivating the harmonious passion for employees, which in turn will facilitate the helping behaviors among employees. In addition, managers should pay more attentions to the employees with lower level of proactive personality, because these employees need someone else to remind them of time, pace, and schedule, so that they are able to complete their jobs effectively and make time to help their colleagues.