A touch display apparatus is provided, which includes a panel and a circuit. The panel is configured for display, active stylus sensing and touch sensing, which includes a sensing layer having sensing blocks arranged in an array of rows and columns. The circuit is coupled to the panel, and is configured to drive the panel to perform display and active stylus sensing with respect to a first reference voltage at a first stage of a frame period and to drive the panel to perform touch sensing with respect to a second reference voltage at a second stage of the frame period.