Abstract: The weak signal detection of bolt in strong noise has been a real engineering problem.Stochastic resonance is different from conventional denoising method，which uses the noise energy to enhance the weak signal buried in noise.The classical stochastic resonance is only suitable for detecting small parameter signal(signal frequency、signal amplitude、noise intensity is much less than 1)，but bolt signal by stress wave reflection method belongs to the damped oscillation transient signal，which has the aperiodicity and large parameter characteristics.Therefore，aperiodic scale transformation stochastic resonance method is adopt to process bolt signal.Based on the advantages and disadvantages of aperiodic stochastic resonance with kurtosis index and correlation coefficient respectively，weighted kurtosis index is used as measurement index.Amplitude is normalization processing and frequency is linear compression in scale transformation stochastic resonance，which meets the requirements of classical stochastic resonance for bolt signal.By processing aperiodic large parameter simulation signal and vibration signal of bolts in practical project，the validity of aperiodic scale transformation stochastic resonance is verified.