中文摘要：

讨论了具有时滞的非自治三种群捕食-食饵扩散系统.利用重合度理论,得到了正周期解存在的一些充分条件.

英文摘要：

A non-autonomous predator-prey diffusive system of three species with delay was analyzed.By using Gaines and Mawhin＇s continuation theorem of coincidence degree theory,some sufficient conditions for the existence of positive periodic solution were established for the system.