The present invention provides a motor having a braking function and used in a linear actuator. The motor includes a main body, a rotation shaft, a braking means and a stopping means. The rotation shaft penetrates the center of the main body. The braking means includes a braking ring and a helical ring. The braking ring includes a plurality of curved plates. The helical ring surrounds outer edges of the curved plates. Each curved plate is put on the outer periphery of the rotation shaft. The stopping means is disposed between the main body and the braking means for restricting the rotation of any of the curved plates. By this arrangement, a better braking and decelerating function can be achieved.