In order to improve the measurement accuracy of transient heat flow based on laser pulse response technology, a dynamic calibration algorithm of heat flow based on pulse response of fiber semiconductor laser is proposed. The system uses a high-power fiber semiconductor laser to generate modulated excitation, and quantitatively detects the transient heat flow energy in the form of pulsed radiation. The light intensity of the light source is adjusted by the homogenization of the light spot, and the energy measurement is completed with a Gardon meter. The data acquisition card and signal analysis circuit are used to realize the high-speed calculation and acquisition of the heat flow signal. Using the transient quantitative identification algorithm, the dynamic test performance of a circular foil heat flow meter of the GD series is tested and calibrated. The simulation analysis of the system’s ability to modulate the signal verifies the feasibility of the system’s light source modulation. A transient quantitative identification system based on high-power fiber semiconductor lasers is established in the experiment. The data curve noise after passing this algorithm is smaller and the accuracy is higher, which verifies the effectiveness of the algorithm. The algorithm can be applied to the field of rapid quantitative identification and analysis of transient heat flow energy.