The modulation of electrostatic potential and optoelectronic characteristics of Janus MoSSe/MX2 (M [Formula: see text] Mo, X [Formula: see text] S, Se) van der Waals (vdW) heterostructures with strain engineering were studied by first principles. Based on the effection of uniaxial strain, the electronic properties of heterostructures not only are induced to form direct band gap and indirect band gap and even semiconductor-metal transformation, but also lead to strong interface-built electric field and excellent optical adsorption properties in the range of IR-visible. This work reveals the photophysical properties of MoSSe/MX2 vdW heterostructures as well as shows their strong potential for applications in novel optoelectronic devices and photocatalysis.