In this paper, the authors deal with the basic principle for nondestructive test of the pile inclination. Based on the implementation of the seismic alignment on the top of the pile, it is found that the larger the inclination degree of the pile, the bigger its side effect, and that, when the pile is inclined, the main response on the side of the pile is the primary wave and the transverse wave. An experiment on the pile inclination with the help of a three-component detector has proved these conclusions.