The invention discloses a parallel hybrid electric vehicle energy management method with gearbox gear control, and relates to the field of hybrid electric vehicle energy management. The parallel hybrid electric vehicle energy management method analyzes an evolution law of a state of charge change rate of a battery and engine specific fuel consumption under each gear, combines with a hybrid logic dynamic modeling method, establishes a parallel hybrid electric vehicle energy management system model including gearbox discrete gear information, further introduces a model predictive control idea, defines motor torque as a continuous control variable, and defines gearbox gears as discrete control variables and translates an optimization problem into a mixed integer quadratic programming problemto solve, the strategy optimizes the torque distribution of each power source and decides an optimal gearbox gear. The parallel hybrid electric vehicle energy management method aims at the energy management problem of a parallel hybrid electric vehicle with a gearbox, and has the advantages of high pertinence, high practicability, good optimization effect, high integration and the like.