The Tevatron experiments provide us very good information for the QCD modelings of event generators. However, in the LHC era, the collisions is in di fferent region of phase-space from that of Tevatron. A Naive rescaling of cross-sections will not work. The current modeling of non-trivial interplay of perturbative (multiple parton interactions) and non-perturbative (beam remnants, ISR, FSR) aspects based on Tevatron data have large di fferences when extrapolated to the LHC energy. The charged particle and transverse momentum densities relative to the leading jet in di erent regions are examined. The simulation is done with the CMS detector under the start-up LHC conditions where the pile-up e ect can be neglected. This study is devoted to discriminating among di erent models and to help us to understand the QCD Monte Carlo models. Information obtained from this study will be useful to improve/tune Monte Carlo models which were only validated with the low energy Tevatron data.