The invention provides a method and a device for controlling dissipation balance of a full-bridge module, the method comprises the steps that when Uc and -Uc levels are output by a sub-module, the time delta t when positive and negative levels are output is divided into two stages delta t 1 and delta t 2, the delta t is equal to the sum of the delta t 1 and the delta t 2, two kinds of states are divided in each time period, two kinds of states are divided in the time period delta t 1, a switching tube T1 and a switching tube T2 are conducted alternatively in the delta t 1, and a switching tubeT3 and a switching tube T4 are conducted alternatively in the delta t 2. In the period when the positive level Uc is output and in the period when the switching tube T1 and the switching tube T2 areconducted alternatively, the normal conductive state of the tube T4 is kept, and in the period when the switching tube 3 and the switching tube 4 are conducted alternatively, the normal conductive state of the tube T1 is kept; in the period when the negative level Uc is output and in the period when the switching tube T1 and the switching tube T2 are conducted alternatively, the normal conductivestate of the tube T3 is kept, and in the period when the switching tube T3 and the switching tube T4 are conducted alternatively, the normal conductive state of the tube T2 is kept. According to the method and the device for controlling the dissipation balance of the full-bridge module, rising of the junction temperature of each device of the module due to unbalanced power dissipation of each power device of the full-bridge module is avoided, and the power output capacity of the whole module is improved.