A review and evaluating the completeness of the experimental study on the thermodynamic properties (TDP) of propylcyclohexane in various ranges of state parameters has been carried out. The analysis revealed a lack of experimental data in some areas of the state surface. Therefore, in order to ensure the stability of the equation of state and good extrapolation qualities, some calculated data on thermodynamic properties obtained by various methods were used for unexplored areas. At the same time, proven methods of generalized calculation developed within the framework of the theory of thermodynamic similarity were used. A fundamental equation of state (FES) for propylcyclohexane is obtained, applicable in the temperature range from the triple point to 700 K at pressures up to 100 MPa. The equation is based on the hybrid array of experimental and calculated data using a heuristic algorithm based on the random search method. The equation describes the reduced Helmholtz potential in variables - reduced temperature and reduced density, contains 11 terms, of which six are polynomial and five are exponential. The equation satisfies the conditions of the critical point, Maxwell's rule and the rectilinear diameter, the positiveness of the heat capacity, and also correctly conveys the course of ideal curves and derivatives of the thermodynamic potential. The average relative deviations for the calculated values of TDP according to the FES have the following values: density of the liquid phase – ±0.31%, saturation vapor pressure – ±0.42%, density of the saturated liquid phase – ±0.18%, isobaric heat capacity of the liquid phase at the saturation line – ±0.54%; and sound speed – ±0.17%.