Inorganic non-toxic metal halide perovskites have taken the dominant place in commercialization of the optoelectronic devices. The first principles simulation has been executed with the help of density functional theory to investigate the structural, optical, electronic and mechanical properties of non-toxic CsSnCl3 metal halide under various hydrostatic pressures up to 40 GPa. The analysis of optical functions displays that the absorption edge of CsSnCl3 perovskite is shifted remarkably toward the low energy region (red shift) with enhanced pressure. The absorptivity, conductivity and the value of dielectric constant also increases with the applied pressure. The investigation of mechanical properties reveals CsSnCl3 perovskite is mechanically stable as well as highly ductile and the ductility is increased with increasing pressure. The investigation of electronic properties shows semiconducting to metallic transition occurs in CsSnCl3 under elevated pressure. The Physics behind all these changes under hydrostatic pressure has been analyzed and explained in details within the available Scientific theory.