A High-Definition Multimedia Interface (HDMI) receiving circuit receives an image signal and an input clock transmitted via HDMI and generates output data. The HDMI receiving circuit includes: a sampling circuit, sampling the image signal according to a transmission mode and the input clock to generate the output data; a data comparison circuit, coupled to the sampling circuit, determining whether the output data includes predetermined data to generate a determination result; and a control circuit, coupled to the sampling circuit and the data comparison circuit, determining the transmission mode according to the determination result.