A virtual reality system, comprising: a host device; a transmission cable; and a head mounted display apparatus adapted to be worn by a user and coupled to the host device via the transmission cable, comprising: a multimedia module, adapted to receive multimedia content from the host device via a first signal path of the transmission cable and to process and play the multimedia content; a multi-sensing module, adapted to obtain sensing information regarding the head mounted display apparatus and the user; a peripheral hub, adapted to receive communication data from the host device via a second signal path of the transmission cable, and to provide the sensing information to the host device via the second signal path of the transmission cable; a power management device, adapted to control power status of the multimedia module, the multi-sensing module, and the peripheral hub according to a power voltage from the host device via a third signal path of the transmission cable; and a micro control unit, adapted to detect in which mode the virtual reality system is operating according to signal status of the first and second signal paths of the transmission cable, and adapted to notify the power management device to control the power status of the multimedia module, the multi-sensing module, and the peripheral hub, wherein the host device comprises a computing device adapted to generate the multimedia content according to a multimedia source and according to the sensing information received from the head mounted display apparatus, wherein the computing device is adapted to generate the communication data according to the sensing information, wherein the sensing information comprises position information, user information or environment information. a host device; a transmission cable; and a head mounted display apparatus adapted to be worn by a user and coupled to the host device via the transmission cable, comprising: a multimedia module, adapted to receive multimedia content from the host device via a first signal path of the transmission cable and to process and play the multimedia content; a multi-sensing module, adapted to obtain sensing information regarding the head mounted display apparatus and the user; a peripheral hub, adapted to receive communication data from the host device via a second signal path of the transmission cable, and to provide the sensing information to the host device via the second signal path of the transmission cable; a power management device, adapted to control power status of the multimedia module, the multi-sensing module, and the peripheral hub according to a power voltage from the host device via a third signal path of the transmission cable; and a micro control unit, adapted to detect in which mode the virtual reality system is operating according to signal status of the first and second signal paths of the transmission cable, and adapted to notify the power management device to control the power status of the multimedia module, the multi-sensing module, and the peripheral hub, a multimedia module, adapted to receive multimedia content from the host device via a first signal path of the transmission cable and to process and play the multimedia content; a multi-sensing module, adapted to obtain sensing information regarding the head mounted display apparatus and the user; a peripheral hub, adapted to receive communication data from the host device via a second signal path of the transmission cable, and to provide the sensing information to the host device via the second signal path of the transmission cable; a power management device, adapted to control power status of the multimedia module, the multi-sensing module, and the peripheral hub according to a power voltage from the host device via a third signal path of the transmission cable; and a micro control unit, adapted to detect in which mode the virtual reality system is operating according to signal status of the first and second signal paths of the transmission cable, and adapted to notify the power management device to control the power status of the multimedia module, the multi-sensing module, and the peripheral hub, wherein the host device comprises a computing device adapted to generate the multimedia content according to a multimedia source and according to the sensing information received from the head mounted display apparatus, wherein the computing device is adapted to generate the communication data according to the sensing information, wherein the sensing information comprises position information, user information or environment information.