The invention discloses a degraded eavesdropping channel rate compatible method based on a punctured Polar code. According to the method, the punctured Polar code is combined with a degraded eavesdropping channel model; according to construction features of the Polar code, a safe bit-channel used for transmitting information is given; according to channel rate requirements of a degraded eavesdropping channel, a proper puncturing matrix is built, and the degraded eavesdropping channel rate compatible method based on the Polar code is achieved; because eavesdroppers do not know the puncturing matrix, the coded code word length is reduced through puncturing operation, information is hidden through the puncturing operation, the complexity that the eavesdroppers recover original information through code words received through wiretapping is increased, and system safety is guaranteed; furthermore, the puncturing method ensures that all codes in the same group of rate-compatible codes can be achieved through the same group of encoders, and therefore the complexity of emitters and receivers is greatly reduced.