The invention provides a non-overshooting temperature control algorithm for a CT detector. The algorithm comprises the following steps: system initialization: setting target temperature, detection point temperature difference, PID parameter, sampling number, target temperature AD value, ADC reference voltage and PWM output restriction; temperature measurement: collecting the temperature at a testpoint through a NTC thermistor; fault judgment: judging whether a working state and temperature of a temperature probe are in a normal range; if the working state and temperature of the temperature probe are in the normal range, computing the heating power by adopting the PID, and then performing the heating; producing negative error through a proportional parameter Kp by adopting the formula different from the conventional PID algorithm; and judging weather reaches the target temperature. Through the new PID algorithm design, the Kp is still in continuous effect to commonly maintain the balance with the integral parameter Ki even reaching a steady state, the overshooting can completely disappear. The temperature of the detector module can be controlled at 37 DEG C+/-1 DEG C by adopting the technical scheme disclosed by the invention, and the algorithm is fast and free from overshooting.