An exemplary heat dissipation fan includes a rotor and a stator. The stator includes a stator core. The rotor is rotatably mounted around the stator. The rotor includes a hub and a magnet ring received in the hub. The hub includes a top wall and a peripheral side wall depending from the top wall. The magnet ring is attached to the side wall and surrounding the stator. The magnet ring has a larger thickness as measured in a radial direction at a first end which is far away from the top wall than a second end which is adjacent to top wall, such that an attracting force formed between the first end of the magnet ring and the stator core is larger than that formed between the second end of the magnet ring and the stator core.