The invention relates to a high-strength molded septic tank. The high-strength molded septic tank comprises a shell, inspection residue outlets, a water inlet, a water outlet and separator plates arranged in the shell, every separator plate is provided with an opening, the shell comprises an upper shell and a lower shell, each of the upper shell and the lower shell is provided with a mounting edge, every mounting edge is provided with mounting holes used for bolt fastening, the upper shell and the lower shell are fixed and mounted through bolts to form an integral structure, the water inlet, the water outlet and the inspection residue outlets are arranged on the upper shell, and mounting slots used for fixing the separator plates are arranged in the lower shell. The high-strength molded septic tank adopting an SMC molding technology and a high temperature and high pressure forming technology has high density, has comparable strength with metal products, has smooth and clean surface, has no pores or joints, does not seep, and has light weight; the upper shell and the lower shell can be transported in a stacked manner, so the shipped quantity per truck is large, the septic tank is convenient to transport, and the transportation cost is saved; and the upper shell and the lower shell are connected through adopting glass cement (or a sealing ring) and the bolts, so the septic tank can be easily mounted in the construction field.