The invention relates to an automotive self-adaptive rainfall sensing circuit which comprises a microcontroller, an LIN interface circuit, a temperature sampling circuit, a temperature adjusting circuit, an infrared light modulation and detection circuit, a natural light detection circuit, a debugging interface circuit, a state indication circuit, a power supply circuit, a clock circuit, wherein the LIN interface circuit is in signal connection with a serial communication port of the microcontroller, the temperature sampling circuit is in signal connection with a digital sampling port of the microcontroller, the temperature adjusting circuit is in signal connection with an I/O port of the microcontroller, the infrared light modulation and detection circuit is in signal connection with the I/O port of the microcontroller, a natural light detection circuit is in signal connection with the I/O port of the microcontroller. The invention has the advantages of adjustable rain intensity level and high flexibility.