混凝土超声波换能器的t0读数通常采用标准棒的方式测量和扣除。揭示了按照检测规范要求，取超声首波波幅为“等幅读数”时，由于检测人员思维的习惯性，机械教条地运用该操作方法，产生了t0读数误差的原因，这将造成混凝土声速计算错误的不良结果。提出了运用标准棒扣除换能器t0读数时的正确操作方法。

Usually we measure and deduct the t0 reading of concrete ultrasonic transducer by using the standard bar. But when taking the head wave amplitude as “the constant-amplitude reading” according to the testing standard, it always causes the error of t0 reading. The routine thought of operator and doctrine using of this operating procedure will certainly lead to the mistake of sonic speed miscalculation. It was showed the collect ways of deducting the t0 reading of transducer by using standard bar.