A projection lamp includes a transparent first shell, a second shell connected with the first shell, a light source seat, a light source fixed on the light source seat, a hollow cylinder-shaped light processing cylinder, and a driving device connected with the light processing cylinder. The light source and at least one part of the light source seat are received in the light processing cylinder, and do not rotate along with the light processing cylinder. The projection lamp of the present invention utilizes the light processing cylinder, so that a pattern projected is in a rolling state, and is unlikely to cause a dizzy feeling. Due to the fact that the transparent first shell is adopted, through a preset light processing effect designed on the first shell, the change of the projected pattern is more abundant and more interesting.