The alien stone turning-milling compound machining center（HTM50200）is the new generation multifunctional compound machining center. It is used to process rotating alien stone products and three-dimensional sculpture products. Pillar is the key support part of the machining center. The parallelism, straightness, levelness of the pillar affects the straight-line movement precision of beam parts. Therefore, the assembly precision debugging of the pillar plays the decisive role in the overall accuracy of this machining center. This paper introduces a kind of method by laser interference adjusting the assembly accuracy of the pillar. The results meet the design requirements of the assembly accuracy of pillar. It lays a solid foundation for the following-up assembly of the alien stone turning-milling compound machining center.