Display device and audio control method thereof

A display device, capable of providing a first audio, is coupled to a host device through a first interface, the display device has a first output volume value, and the host device has a second output volume value, the display device comprising:

• a main control element, used to adjust the first output volume value according to a first control command, and compare the first output volume value with an upper limit value or a lower limit value to generate a first comparison result;
• an output element, coupled to the main control element and the host device, and used to generate the first audio according to the first output volume value and the second output volume value;
• and
• an interface control element, coupled to the main control element and an input element, coupled to the host device through the first interface, and used to selectively generate a second control command according to the first comparison result and the first control command,
• wherein, when the first control command indicates increasing the first output volume value and the first comparison result indicates that the first output volume value is equal to the upper limit value, or when the first control command indicates decreasing the first output volume value and the first comparison result indicates that the first output volume value is equal to the lower limit value, the interface control element generates the second control command and sends the second control command to the host device through the first interface, and the host device adjusts the second output volume value in response to the second control command.