First, the localization of QRS complex in each lead is detected by using hypothesis testing on electrocardiograph(ECG) signal's wavelet transform, and the probability of false alarm and the probability of miss are also computed. Then, the peak comparison fusion and decision weightiness fusion are applied to 12 leads' decision to obtain the precision lccation of each QRS complex. The experiments show that we are able to detect the QRS complex correctly for various pathological ECGs by this method, and the correct detection rate of QRS complex can be above 99.95%.