The electronic structures and anisotropic transport properties of doped-GeSe monolayers are systematically explored by performing the density functional theory combined with non-equilibrium Green’s function method. Numerical results of the cohesive energy and formation energy show that it is possible to substitute Ge/Se with isovalent atoms and group-V atoms at room temperature. Isovalent substitutions of Ge/Se atoms can maintain the semiconducting features of monolayer GeSe. While the doping of group-V atoms modifies drastically the electronic structures of doped-GeSe and makes metallic properties appear. In addition, the anisotropy of electronic transport of monolayer GeSe also can be effectively manipulated by substitutional doping. In particular, the isotropic electronic transport properties are shown in the devices based on GeSe with P substituting Ge atom. An obvious negative differential resistance behavior with a large current peak-to-valley ratio up to the radio of 103 is gained in N-dope device. These results are useful for the future potential applications of GeSe materials in next-generation high-efficiency electronic devices.