Molecular dynamics Simulations of a semi-flexible main chain LCP (liquid crystalline polymer) have been carried Out using a newly developed model named solo-LJ-spring-GB model. The new model represents the molecular chain in the form of GB-spring-LJ-spring-...-LJ-spring-GB sections that simplifies the model and reduces the simulation computation by many times. The new model was evaluated by studying the phase behaviors of semi-flexible main chain LCPs through simulation. The results, such as the spontaneous phase transition front isotropic phase to nematic phase as the system temperature decreases and the odd-even effect of the number of flexible spacers on its thermodynamic properties agree well with other experimental results as well as simulations using the traditional GB/LJ model. The orientational and translational mobilities of mesogenic units in the new model have also been measured and compared with those in the traditional GB/LJ model with very little differences found. (c) 2005 Elsevier Ltd. All rights reserved.