Abstract: In this paper, we collect the radio data(core and the extended luminosity) for the radio selected and X-ray selected BL Lacertae objects, and calculat their core-dominance parameter R. Our results show that the total radio luminosity of radio selected BL Lacertae objects-RBLs is two decades higher than that of X-ray selected BL Lacertae objects-XBLs. A detailed analysis suggests that the difference is from the fact that the core luminosity of RBLs is two decade of decades more powerful than that of XBLs since the extended luminosity is only a decade more powerful than that in the XBLs. We also investigate the correlation between the core/extended luminosity and the core-dominance parameter, the extended luminosity is anti-correlated with the core-dominance parameter, however, there is almost no correlation between the core/total luminosity and the core-dominance parameter for each subclass.