An assistant starting method of electronic parking brake system for a motor vehicle, in which the electronic parking brake system receives all sensor signals and detection signals of the motor vehicle, the method is characterized in that, the sensor and detection signals received by the electronic parking brake system from the motor vehicle to determine whether to release the brake include the engine rotate speed signal obtained from the sensors on the engine and the effective torque signals output by the engine, a clutch pedal signal, an acceleration pedal signal, an acceleration signal, and a rotate speed or angle of a driving wheel, wherein a torque Tc transmitted by a clutch is calculated based on the engine rotate speed signal and the effective torque signals output by the engine; when any one of the following conditions is satisfied, the brake will be released to assist a driver in starting: Condition: the calculated torque T c transmitted by the clutch is greater than a torque T n needed for starting the motor vehicle; Condition: an engine rotate speed is greater than an engine idle speed, and an accelerator pedal and a clutch pedal are depressed simultaneously; Condition: starting trend of the motor vehicle is detected; Condition: the detected engine rotate speed is lower than a first predetermined threshold value calculated according to a throttle opening data; Condition: a detected rotate speed or angle of a driving wheel is greater than a predetermined threshold value of rotate speed or angle, and wherein under condition, the torque T c transmitted by the clutch is calculated through the following equation: T c = T e − I e ⋅ α e = T e − I e ⋅ Δ ω e Δ t = T e − π 30 ⋅ I e ⋅ Δ n e Δ t wherein, T c The torque transmitted by the clutch is the final calculated result; T e The effective torque output by the engine, corresponding to the received engine torque signal; I e The moment of inertia of the engine is a constant stored in the storage unit; α e The angular acceleration of the engine is an intermediate variable; ω e The angular speed of the engine is an intermediate variable; n e The rotate speed of the engine, corresponding to the received engine rotate speed signal. Condition: the calculated torque T c transmitted by the clutch is greater than a torque T n needed for starting the motor vehicle; Condition: an engine rotate speed is greater than an engine idle speed, and an accelerator pedal and a clutch pedal are depressed simultaneously; Condition: starting trend of the motor vehicle is detected; Condition: the detected engine rotate speed is lower than a first predetermined threshold value calculated according to a throttle opening data; Condition: a detected rotate speed or angle of a driving wheel is greater than a predetermined threshold value of rotate speed or angle, T c The torque transmitted by the clutch is the final calculated result; T e The effective torque output by the engine, corresponding to the received engine torque signal; I e The moment of inertia of the engine is a constant stored in the storage unit; α e The angular acceleration of the engine is an intermediate variable; ω e The angular speed of the engine is an intermediate variable; n e The rotate speed of the engine, corresponding to the received engine rotate speed signal.