Abstract: For the traditional elevation method to determine the fatigue limit specimens require a large number of demand, take a long time, costly and other characteristics, a temperature rise based evolution of stainless steel-carbon steel heterogeneous material spot welded joints fatigue limit fast prediction method is discussed. Through the SUS301L-Q235B spot welded joints single specimen for step-by-step stress loading, and with the help of infrared thermal imaging camera to obtain real-time temperature changes in the specimen, and then based on the establishment of the fatigue limit prediction model to calculate the fatigue limit value of 4.883 kN. traditional lifting method test to determine the fatigue limit value of 5.00 kN, the error between the predicted value and the test value of 2.34%. The above illustrates the prediction of fatigue limit of the spot welded joints with infrared thermal imaging method is accurate, providing a new idea for fatigue limit prediction assessment.