The applicability of several commonly used de - noising methods is examined in signal analysis of instant vibration testing for soil compactness . the analysis result indicates that the method based on wavelet thresholds is the best . the method for determination the threshold of wavelet de - noising is also proposed to satisfy soil compactness test signal 对比了几种常用信号降噪方法在土密实度瞬态振动测试信号中的适用性,得到了小波阈值降噪法最适用于土密实度瞬态锤击测试信号的结论,并给出了适用于土密实度测试信号降噪的小滤阈值确定方法。