The invention discloses a train wheel axle weight adjustment method, a traction force and braking force distributing method and system. The traction force and braking force distributing method comprises the following steps: collecting the pressure value and the height direction displacement of an air spring of a bogie and the pressure value of a primary spring; according to the pressure value of the air spring, controlling the air spring to inflate or release the air, according to the height direction displacement of the air spring, adjusting the height of the air spring, and adjusting all pressure values of the air spring of the vehicle bogie to be equal to enable the weight of the vehicle wheel axle to be uniformly distributed; when a train pulls, controlling the output torque of a tractive electromotor to be matched with the weight of each axle of the vehicle according to the pressure value of the primary spring so as to distribute the tractive force of the vehicle; and when the vehicle brakes, according to the pressure value of the primary spring, controlling braking force output of an adhesion braking system in different forms on each braking wheel to distribute the vehicle braking force. The traction force and braking force distributing method can improve wheel axle weight distribution, precisely distributes tractive force and braking force, increases the adhesion utilization degree of the train and improves the power performance of the train.