Construction of van der Waals heterostructure provides a straightforward way to blend properties of different monolayer materials for enhanced photovoltaic performance. Herein, motivated by the successful characteriza-tion of monolayer SnX2 (X = S, Se) and arsenene (As), detailed interfacial interaction and optical absorption proficiencies of novel SnSSe/As heterostructure have been systematically investigated. Findings reveal that the SnSSe/As heterostructure exhibits a type-II band arrangement with an indirect bandgap of 1.30 eV that ap-proaches the desirable Shockley-Queisser Limit under 2% biaxial tensile strain, strong absorption of 104-105 cm-1 toward solar irradiation that encompasses the infrared-ultraviolet region and high carrier mobility up to 910.71 cm2 V-1 s-1. Large, negative binding energy and absence of chemical bonds at the heterostructure interface imply its stability. The dynamical and mechanical stabilities have also been confirmed. Moreover, analysis of oxygen adsorption suggests tolerable performance deterioration with SnSSe side facing the ambient air. Hence, a photovoltaic with power conversion efficiency (PCE) exceeding 30% is ultimately proposed.