The present invention discloses an ear mould, working by cooperation with a receiving device which put in ear canal. The ear mould includes a head of the ear mould and a sound transmission device which connected with the head. The sound transmission device is used for connection with the speaker of the hearing aid. The head of the ear mould is integrated with the sound transmission device. An end of sound transmission device wh i ch is connected with the hear i ng aid is elastic. The part of the sound transmission device which is connected with the head of the ear mould is flexible. The present invention also discloses a corresponding open in-ear sound receiving device which is for assisting the positioning and sound transmission of the receiver of hearing aid in the ear canal so that effectively enhancing valid outputting power of the hearing aid.
