A lens module with physically stronger foundations and enhanced stability includes a circuit board, an image sensor thereon, a mounting bracket, an optical filter, and a lens unit. The mounting bracket on the circuit board has the image sensor. The optical filter on the mounting bracket is above the image sensor. The lens unit is connected to the mounting bracket facing away from the circuit board by a frame of adhesive. The surface of the mounting bracket facing away from the circuit board has positioning posts at corners of the surface of the mounting bracket. A surface of the lens unit connected to the mounting bracket has receiving grooves positioned at corners of the surface of the lens unit. The positioning posts are inserted into the receiving grooves.