An electric-motor-assisted supercharging control method for an engine, comprising: disposing a one-way valve and an intake branch connected in parallel to the one-way valve on an intake channel between an air compressor driven by an exhaust gas turbine and an intake manifold, disposing an auxiliary air compressor and an electric motor that drives the auxiliary air compressor on the intake branch, and controlling, according to actual engine parameters, the auxiliary air compressor to operate at a smoothly changing rotation speed, characterized in that the engine parameters comprise a rotation speed, a fuel injection quantity, a coolant temperature, and an intake pressure, wherein a pressure pulse spectrum is made according to the rotation speed and the fuel injection quantity, a coolant temperature correction curve is made according to the coolant temperature, an air pressure correction curve is made according to the intake pressure, the pressure pulse spectrum, the coolant temperature correction curve, and the air pressure correction curve are respectively queried according to the rotation speed, the fuel injection quantity, the coolant temperature, and the intake pressure, a target pressure value is calculated, and a rotation speed pulse spectrum is made according to a pressure difference between the target pressure value and the intake pressure and the rotation speed, and the controlling the auxiliary air compressor to operate comprises the following steps: S1. detecting the rotation speed, the fuel injection quantity, the coolant temperature, and the intake pressure of the engine, and if the rotation speed is less than a preset assisted supercharging rotation speed or the auxiliary air compressor is operating, performing step S2; otherwise, restarting step S1; S2. querying the pressure pulse spectrum according to the rotation speed and the fuel injection quantity to obtain a base pressure value, querying the coolant temperature correction curve according to the coolant temperature to obtain a coolant temperature correction factor, querying the air pressure correction curve according to the intake pressure to obtain an air pressure correction factor, and multiplying the base pressure value sequentially by the coolant temperature correction factor and the air pressure correction factor to obtain a target pressure value; and S3. querying the rotation speed pulse spectrum according to the rotation speed and the pressure difference to obtain a base supercharging rotation speed value, performing PID closed-loop regulation according to the pressure difference to obtain a PID regulation value, adding the base supercharging rotation speed value and the PID regulation value to obtain a target rotation speed value, controlling, according to the target rotation speed value, the auxiliary air compressor to operate, and performing step S1. S1. detecting the rotation speed, the fuel injection quantity, the coolant temperature, and the intake pressure of the engine, and if the rotation speed is less than a preset assisted supercharging rotation speed or the auxiliary air compressor is operating, performing step S2; otherwise, restarting step S1; S2. querying the pressure pulse spectrum according to the rotation speed and the fuel injection quantity to obtain a base pressure value, querying the coolant temperature correction curve according to the coolant temperature to obtain a coolant temperature correction factor, querying the air pressure correction curve according to the intake pressure to obtain an air pressure correction factor, and multiplying the base pressure value sequentially by the coolant temperature correction factor and the air pressure correction factor to obtain a target pressure value; and S3. querying the rotation speed pulse spectrum according to the rotation speed and the pressure difference to obtain a base supercharging rotation speed value, performing PID closed-loop regulation according to the pressure difference to obtain a PID regulation value, adding the base supercharging rotation speed value and the PID regulation value to obtain a target rotation speed value, controlling, according to the target rotation speed value, the auxiliary air compressor to operate, and performing step S1.