The invention belongs to the technical field of power systems and automation thereof and more specifically relates to a transmission section limit solving method based on a method for adjusting opposite and equal quantities in pairs. The solving method is characterized by, firstly, in a normal operating mode, selecting a typical load mode, and forming raw data of ground state power flow; finding an operating branch with the maximum active power, cutting off the branch and transferring the flow of the branch to other branches; finding a branch l, which is the most likely to exceed a limit, from the other branches; calculating the sensitivity of each unit in a sending and receiving end region to the branch l, calculating an adjustment amount until the branch l is overloaded, and making adjustment reversely after the overload until the branch l is not overloaded; and calculating the sum of flow of all the branches at the moment, i.e. the transmission section limit. The solving method sorts all the controllable units according to the sensitivity, and pairs the units with the maximum sensitivity and the minimum sensitivity for each paired adjustment. The adjustment does not rely on a balance machine, and the result is more reasonable and reliable.