The invention relates to an uncooled thermal infrared imager continuous zooming and fast automobile focusing circuit and method. A hardware part and a method part are provided. According to the hardware part, proper elements are selected to form the circuit with continuous zooming control and automobile focusing functions. The circuit has the advantages that power consumption is low and the size of a circuit board is small. The circuit can be applied to different systems conveniently. The circuit mainly comprises a major power supply circuit, a data acquisition circuit, a master control system circuit, a motor driving circuit, a position feedback circuit and a serial port control circuit. According to the method part, continuous zooming control is achieved through linear segmentation fitting, and a zoom cam curve is precisely simulated; automobile focusing is achieved through the combination of fuzzy control and the Tenengrad evaluation function, and objective focusing is achieved quickly and accurately through self-adaptive focusing of step length.