基于超声波首波波幅改变对混凝土声时测值的影响程度，分析研究了超声波检测仪首波波幅变化与混凝土强度计算值之间的关系。结果表明，同一试件，由于首波波幅的不同而造成声时测值的误判，将导致混凝土强度值的计算产生很大的误差。研究表明，为了减小声时测值的误差，必须以规定的首波幅度读取的声时值计算混凝土强度。

This paper analyzed the influence of the ultrasonic head wave amplitudes change to the concretes sonic time value, and studied the relationship between the ultrasonic wave instrumentation head wave amplitudes change and the predicted value of concretes intensity. The result showed that the false positives of measured sonic time value caused by the ultrasonic head wave amplitudes difference, had led to large error in concretes intensity measure. In order to reduce the mistake of sonic time value, it must stipulate head wave scope read sound when calculating concretes intensity.