An assembling method of a camera module includes the following steps. Firstly, a sensing chip is installed on a strip-like substrate. Then, the strip-like substrate is bent, so that a bent substrate in a bent state is formed. Then, the bent substrate and an optical lens are placed on a fastening table and an alignment module, respectively. Then, an installation angle of the optical lens is adjusted by the alignment module according to an active alignment. Then, the optical lens and the bent substrate are combined together. After the bent substrate is restored from the bent state to a non-bent state, the camera module is produced. The assembling method is suitable for assembling the longer camera module.