In this paper, an empirical regularity has been proposed for dense fluids, namely, that the thermal pressure coefficient is a near-parabola function of pressure. The regularity has been tested with experimental data for both associating and nonassociating compounds. The applicable ranges have also been investigated widely. It is found that the regularity holds well from the freezing temperature to critical temperature, and no obvious limits were found for pressure and compound type. Moreover, parameters of the thermal pressure coefficient expression were regressed from experimental data for n-alkanols, and the statistical results show it is an accurate correlation equation. Further, on the basis of the Lennard-Jones (12-6) potential function, the theoretical analysis was given to confirm the existence and uniqueness of the peak point for Lennard-Jones fluids.