The present invention provides a virtual machine system and a method of accessing a graphics card. The virtual machine system includes a VMM, an SOS and at least one GOS, and further includes a resource converting module for performing IO address converting on graphics card framebuffer accessing data from GOS(s) or mapping MMIO(s) to physical MMIO(s) of a graphics card based on a resource converting table, and sending the processed data to the graphics card; and a framebuffer allocating module for dividing a framebuffer resource of the graphics card into multiple blocks and allocating them respectively to corresponding GOS(s). The resource converting table(s) records correspondences between a resource allocation for the graphics card by SOS and a resource allocation for the graphics card by GOS(s). The framebuffer MMIO resource(s) allocated to the graphics card by GOS(s) is/are the framebuffer allocated to GOS(s) by the framebuffer allocating module.