In this paper, a model of Si atom adsorbed on black phosphorene with a coverage of 2.778% is constructed and the electronic properties of the model are calculated based on density functional theory. Moreover, the electronic properties are regulated by stress and electric field. Under the coverage of the current research, the results show that the adsorption of Si atoms results in the destruction of the black phosphorene’s geometric symmetry, which intensifies the charge transfer in the system and completes the orbital re-hybrid. The band gap of black phosphorene thus disappears and the transition from semiconductor to quasi metal is completed. The stable adsorption is at the H site in the middle of the P atomic ring. Both tensile field and electric field reduce the stability of the system. Owing to the tensile deformation, the band gap is opened by the structure of Si atom adsorbed on black phosphorene. And since the band gap is proportional to the deformation variable, it can be regulated and controlled. Under the combined action of electric field and tensile, the introduction of the electric field leads the band gap of Si adsorbed on black phosphorene system to be narrowed and the transition from the direct band gap to an indirect one to be completed. The band gap still goes up in proportion to the increase of deformation. The band gap of Si atom adsorbed on black phosphorene system is more adjustable than that of the Si atom that is not adsorbed on black phosphorene system, and the stable adjustment of the band gap is more likely to be realized.