The invention discloses a power control system of a hybrid heavy duty truck with a super capacitor. The system comprises an engine, a generator, a rectifier, an inverter, a motor controller and a motor which are sequentially connected, a storage battery and a first bidirectional DC-DC converter which are sequentially connected, a super capacitor and a second bidirectional DC-DC converter which aresequentially connected, a battery capacitance control unit, a signal acquisition unit, a triaxial gyroscope, a GPS positioning device and a power controller. Based on the control system, the invention further discloses a power control method of the hybrid heavy duty truck with the super capacitor, the road conditions on which heavy duty trucks frequently travel are related to super capacitor charging and discharging, so that the reasonable power matching is realized, the power performance, fuel economy and emission performance of the hybrid heavy duty truck are improved, the service life of the storage battery is prolonged, the energy recovery and utilization are realized, and the energy is fully saved.