A camera module (100) includes a lens module (10) and an image sensor (20), wherein the lens module includes a barrel (12), a plurality of lenses (14) and at least one spacer between each two neighboring lenses. The barrel includes an inner wall (122), the lenses and the spacer both are received in the barrel; the image sensor is located on an imaging plane of the plurality of lenses. At least one through slot (18) is defined in at least one item selected from the group consisting of lenses, spacer, and between the lenses and spacer. At least one groove (124) is defined between the inner wall of the barrel and the group consisting of the lenses, spacer and the image sensor. The at least one through slot communicates with at least one groove.