Disclosed is an electric control diesel engine partial throttle injection quantity control method. The method includes allowing a control unit to acquire a rotation speed signal; allowing the control unit to acquire an accelerator pedal voltage signal and fault information; calculating the accelerator pedal opening degree; determining a calibrated speed according to the accelerator pedal opening degree; calculating the partial throttle rotation speed corresponding to a diesel engine external characteristic curve; determining an external characteristic torque data table according to the acquired rotation speed signal and 100% throttle, and acquiring torque values corresponding to different rotation speeds by querying the data table; querying the oil quantity through an oil quantity data table according to the external characteristic torques and the rotation speeds; determining a theory governing rate data table according to the throttle, and acquiring the corresponded governing rate by querying the theory governing rate data table according to different throttle opening degrees; comparing the acquired rotation speed signal with the calculated rotation speed; if the rotation speed of the acquired signal is larger the calculated rotation speed, outputting the injection quantity as a calculated one according to the determined governing rate; if the rotation speed of the acquired signal is smaller than the calculated rotation speed, outputting the injection quantity as one of the external characteristic curve.