Abstract: A new approach for cycle-slips detection and location based on continuous wavelet transform is proposed.GIPSY software can detect and correct the outlier and the cycle-slips using the dual-frequence GPS data,but its dependability is worth doubting in estimating the small cycle-slips.The signals are analyzed by wavelet that is the first derivative of Gaussian function,because the continuous wavelet transform(CWT) has the good character to diagnose the indiscoverable faults,the module maximum value points of signal containing noise have different trend respectively at different scales.It is showed that it can even find(0.5) or 1 cycle slip,so it can apparently improve efficiency of cycle-slips detection algorithm.An example is taken to prove the validness of the method.