Based on the principle about suppression of chaos with parametric nonresonant drive in the Lorenz system, the detection of weak periodic pulse signals in strong noise was realized. Periodic pulse signal, whose frequency is much more larger than the system characteristic frequency, was introduced as the system internal drive signal. According to the parametric equivalent relation obtained by the averaging method and renormalization method between the controlled Lorenz system and the original system, the critical value of detection parameter was determined. Simulations results show that rather low signaltonoise ratio in detection can be obtained by the proposed system. This method can predict the range of parameter threshold by theoretical analysis result. The detection scheme is simple and feasible, which is fit for generalization and application in object detection and fault diagnosis.