On the basis of density functional theory, we investigate the characteristics of n- and p-type dopants in the InSe monolayer by group V and VII atoms substituting Se atom. The results show that group V and VII atoms substituting Se atom have significant influences on the electronic structures of the InSe monolayer, and all the considered doping cases can be easier to be realized under In-rich experiment conditions. For group V atom-doped InSe monolayer, the magnetic ground states are obtained and its transition levels are too large to provide effective p-type carrier. In contrast, for group VII atom, I atom substituting Se atom has lower formation energy and shallowest transition level, which indicates that I substituting Se atom can induce effective n-type doping in the InSe nanosheets.