The invention relates to an airplane braking system for preventing an emergency brake from being improperly used. The airplane braking system comprises a normal braking system and an emergency braking system, wherein the normal braking system comprises a braking command sensor, an electromagnetic hydraulic lock, an electromagnetic servo valve, a control box and an airplane wheel speed sensor; the emergency braking system comprises an emergency braking valve, a converting valve and a switch; and the normal braking system and the emergency braking system are contacted and converted through the converting valve. According to the airplane braking system disclosed by the invention, during emergency braking, if normal braking is also used, the normal braking system is forced to release pressure, so that pressure does not exist in a normal input opening of the converting valve, the situation that the converting valve is completely converted to the emergency braking system is guaranteed, the application of the emergency braking is guaranteed, and emergency braking failure and accident hidden danger caused by that the emergency braking and the normal braking are used at the same time are eliminated fundamentally; and according to the airplane braking system disclosed by the invention, only one electrical switch element is additionally arranged on a conventional braking system, so that conventional equipment is convenient to refit.