Through the study of relationship between generatrix linearity and axes linearity of deep bore, we proposed the new principle and method to measure axes linearity of gunbarrel by measure of generatrix linearity. 从深孔的母线直线度与轴线直线度之间的关系入手,论述了在火炮身管直线度测量中,如何通过测量母线直线度求得轴线直线度的原理和方法。