Heterotopic ossification is the formation of bone in soft tissues that do not normally have ossifying properties. Its main characteristics are: rapid formation of calcified bone in soft tissues, which triggers local redness, swelling and pain of ossification. If the ossification site is around the joint, it can seriously affect the joint movement. There is no effective treatment. Trauma and surgery can induce heterotopic ossification. It is controversial whether to continue rehabilitation therapy such as joint mobilization after heterotopic ossification has occurred. In my opinion, in order to preserve the remaining joint mobility, it is necessary to insist on passive joint movement after the onset of heterotopic ossification, but ROM training should be gentle. If the joint mobility does not affect the ADL, the heterotopic ossification can be left untreated.