In this study, we compared the effect of n-pentane and ice-water bath on removing the thermal effect in the poly (p-phenylene terephthalamide) (PPTA) polymerization process. The results indicate that the n-pentane can help to transfer the reaction heat faster and better. Adding suitable amount of n-pentanes into the PPTA preparation process not only improve the heat transfer, but also reduce the motor power in the polymerization process. Moreover, the introduction of n-pentane properly does not result in decrease of the inherent viscosity (η7inh) of polymer. Instead, it leads to increased viscosity of polymer during the PPTA preparation process. The results indicate that n-pentane can effectively transfer the reaction heat and avoid overheating during the polymerization of PPTA.