To research the coexistent mechanism of 5 kinds of rodents in Hailin region of Heilongjiang Province in september, 2006, we investigated the niche widths of time and the niche overlaps of Sciurus vulgaris, Eutamias sibiricus, Apodemus peninsulae, Myodes rufocanus, M.rutilus with the method of tagging-recapture and indoor observing. Then we analysised the time differentiation of their resources utilization. The results indicated that the phenomena can be divided into two types: the nocturnal ones and the diurnal ones. Niches widths of diurnal ones such as S. vulgaris and E. sibiricus are relatively narrow. They are separately 0.679 and 0.618. On the contrary, the niche widths of the nocturnal ones such as M. rufocanus, M.rutilus, A. peninsular are wider. They are separately 0.935, 0.853, 0.844. The competition between the two species is small. And the niche overlap index is under 0.286, however the competition among the same species is great, and the niche overlap index is over 0.711.To reduce ac, we stagger their activity fastigiums or prolong their activity time to reduce the competition between the different species of the same type.