A portable infrared detection system for electronic circuit fault based on ARM11 is introduced. The thermal image of circuit board to be detected is captured by CCD camera. Then, the image format of the thermal image is transformed by TVP5150, which is used as a video decoder chip. The infrared image will be transported to core processor S3C6410, and the S3C6410 will deal with the thermal image by image processing algorithms. At last, the thermal image of circuit board to be detected will be compared with the thermal image of correct circuit board, and the differences between the two thermal images could come out. The results of experiment show that the detection system has characteristics of high accuracy, high precision and high stability. At the same time, system size is reduced, which makes the system have the better portability. The system could be applied for detecting electronic circuit fault non-intrusively, which make the system have the higher safety.