The invention relates to a method and an apparatus for detecting gender of a human body in a microwave image. The method comprises the steps of accurately locating a chest position and a crotch position of the human body by utilizing structural characteristics of the human body as well as built vertical spatial distribution histogram and horizontal spatial distribution histogram; extracting a chest sub-image of the human body according to the chest position; extracting a crotch sub-image of the human body according to the crotch position; then extracting eigenvalues of the chest sub-image of the human body and the crotch sub-image of the human body by utilizing a characteristic extraction algorithm; and automatically judging the gender of the human body according to the eigenvalues. According to the method and the apparatus, the scheme is simple; through experimental verification, the method and the apparatus can be effectively used in an actual microwave safety inspection system and are good in real-time property and robustness; the correct recognition rate meets a usage requirement; the problem in real-time accurate recognition of the gender of the human body in the microwave safety inspection system is solved; and in addition, the chest position and the crotch position of the human body can be accurately located, so that private parts of the human body can be effectively shielded and protected according to the method and the apparatus.