Abstract: Based on the error analysis of P-wave amplitude measurement, the effect from the mutual positions(axis’s offset and rotation)of the sensors through the experiments was studied. The esult indicated that the rotation can hardly affect the P-wave velocity and amplitude. The axis’s offset can hardly affect P-wave velocity; however, it can affect P-wave amplitude. A set of device was put forward, which can enhance the measure precision of the P-wave amplitude.

Key words: P-wave amplitude, measurement precision, axis’s offset, rotation