Provided are a positioning device of a washing machine drum, and a drum washing machine, which relate to the field of clothes washing apparatuses, and aim at solving the problem in the prior art of low positioning accuracy of a washing machine drum due to being unable to accurately detect a positioning point of the washing machine drum. The positioning device of the washing machine drum comprises an optical signal emitter, an optical signal receiver and a light-transmitting hole (23) arranged on a belt pulley (2) of the washing machine, wherein the optical signal emitter and the optical signal receiver are respectively arranged on two sides of the light-transmitting hole (23), and only when the light-transmitting hole (23) is rotated around a shaft centre of the belt pulley (2) to a position where both the optical signal emitter and the optical signal receiver are aligned, can the optical signal receiver receive an optical signal sent by the optical signal emitter. Therefore, when a drum door of the positioni
