LX tectonic zone steps across two work area. In order to gain more clearly geological structure of LX, 3D seismic data,Block-jointed processing scheme should be put into practice. The orientation of LX tectonic zone is not orthogonality with primary reference frame, and the geodetic coordinates of the second area are missing. In order to acquire better processing effect, a new reference frame is defined again for all work area. The coordinate convert technique not only resolve the problem of missing of geodetic coordinate and the disaccord between two area, but also reveal the geological structure more clearly. Processing result proved that the method can accomplish block-jointed processing successfully.