In our research, we delved into the geometric, electrical, and optical attributes of an innovative MoTe2/ZnI2 heterojunction employing a first-principles approach. We further constructed heterostructure configurations of MoTe2/ZnI2 with different relative positions. The heterojunction in the H1 configuration achieves its highest stability. Upon investigating the electronic characteristics of the heterojunction, it was observed to display Type-II heterojunction behavior, featuring an indirect band gap measuring 0.69 eV. Under the influence of electric fields and stress, the band gap of the heterojunction can shift from a semiconductor to metallic state. Specifically, with a −0.4 VÅ⁻1 electric field, shifting its configuration from Type-II to Type-I. Via an analysis of the optical characteristics of MoTe2 monolayers, ZnI2 monolayers, and the heterojunction. The heterojunction exhibits a generally higher absorbance rate compared to a single layer of ZnI2 and surpasses the absorbance rate of a single layer of MoTe2 in the near-ultraviolet area.