Computer system and method for accessing virtual machine

The invention provides a computer system and a method for accessing virtual machine. The computer system comprises a host operating system installed with a host driver and a virtual machine. The virtual machine comprises a hypervisor and a guest operating system. When the host operating system is intended for accessing the virtual machine, it will issue at least one access instruction to the hypervisor of the virtual machine via the host driver. The guest operating system of the virtual machine receives the access instruction from the hypervisor via a guest driver, and accesses a guest application program, a real hardware, and/or a virtual hardware according to the indication of the access instruction so as to generate an access result. Finally, the guest operating system of the virtual machine is able to transmit the access result to the host operating system.