The optical time domain reflectometer（OTDR） is mainly used in testing the weaken of the entire optical fiber link and providing the weaken detail related to the length

but sometimes surveying curve has error.According to the theory of irregularity examination and processing of signal to eliminate noise using the wavelet analysis

the method of irregularity examination and eliminating noise to the OTDR survey curve using wavelet analysis is proposed.And an experiment to test optical fiber using the OTDR is made.The experimental results display that the actual deviation between reality connection position and position monitored by computer based on wavelet decomposition algorithm is within 4 m

and there is no error in monitoring the normal optical fiber connection

which indicates the feasibility and validity of this method.