A head-mounted display apparatus, a control method, and a mobile platform system are provided. The head-mounted display apparatus includes a housing having an electrical cavity, a first display assembly at least partially disposed within the electrical cavity, and a control assembly configured to control the first display assembly to display an image. The control assembly is disposed within the electrical cavity and at least partially disposed at a side of the first display assembly in a first direction. The first direction includes at least one of a direction away from a face of a wearer or a forward direction of the head-mounted display apparatus.