The invention discloses a two-grade adjustable bypass shunting valve. The two-grade adjustable bypass shunting valve consists of a main pipeline and two secondary pipelines; a switch main valve is arranged on the main pipeline; flow adjusting valves are arranged on the secondary pipelines, and include valve turning plates, fixed baffle plates, rotating handles, auxiliary positioning shafts and spherical rotating shafts; auxiliary positioning shafts are arranged on two sides of the valve turning plates, and are connected to the inner walls of the secondary pipelines through the fixed baffle plates; the spherical rotating shafts are arranged in the centers of the valve turning plates; thin flow through holes are formed in the middle parts of the spherical rotating shafts; the rotating handles include main handles and secondary handles; the main handles are connected to the valve turning plates through rotating shafts; and the secondary handles are connected to the spherical rotating shafts through rotating shafts. Through combined effect of the valve turning plates and the spherical rotating shafts, a selecting switch is adjusted according to actual flow of the flow adjusting valves; and the device is simple in overall structure, precise in operation and control, tight in connection between structures thereof and long in service life.