The Janus VSBrI monolayer, identified by first-principles calculations, emerges as a promising semiconducting material with desirable ferromagnetic and ferroelectric properties. It's in-plane magnetic anisotropic energy is up to 460 $\mu$eV/V , and in-plane and out-of-plane piezoelectric strain coefficients are larger than many other known two-dimensional materials. The energy variations among different magnetic states show a strong correlate with polarization. Interestingly, the stability of the ferroelectric phase can be further enhanced by the application of biaxial tensile strain. These intriguing properties make the Janus VSBrI monolayer highly desirable for practical applications in piezoelectronic devices, and a promising candidate for multifunctional spintronic devices.