Lens assembly, camera, electronic device and assembly method of lens assembly

The invention discloses a lens assembly, a camera, an electronic device and an assembling method of the lens assembly. The lens assembly comprises a driving part and a lens, and the driving part comprises a shell; the lens comprises a first group, a second group and a third group which are arranged on the same optical axis, the first group, the second group and the third group are all arranged in the shell, the first group is arranged on the object side of the second group, the third group is arranged on the image side of the second group, the first group is fixedly connected with the inner surface of the top of the shell, and the second group is fixedly connected with the inner surface of the top of the shell. One end of the inner surface, away from the top of the shell, of the first group is fixedly connected with the third group, and the second group can move along the optical axis of the lens relative to the shell. According to the embodiment of the invention, the first group of the lens assembly is fixed