Abstract: The photogalvanic effect of monolayer molybdenum disulfide (MoS₂) with sulfur vacancies is investigated with first-principle calculations based on the density functional theory within the nonequilibrium Green's function formalism. A detailed analysis of the behavior of photoresponse is given based on the band structure and joint density of states. The results reveal that the linear photovoltaic effect (LPGE) is unconspicuous and the circular photogalvanic effect (CPGE) is obvious. The variation of photoresponse function with polarization angle (phase angle) is simulated and the calculation results are consistent with the phenomenological theory. The monolayer MoS₂ with sulfur vacancies can be applied to novel electronic and optoelectronic devices, which provides a new theoretical basis for further understanding the photogalvanic effect of the monolayer MoS₂ with sulfur vacancies.