ABSTRACT. Many studies had proposed the development of the heat sink by using the straight perforated fin .Today increasing the demand for the more effective design due to the growth of the heat sources in the different energy devices. This paper presents the new design (inclined perforated) of the pin fin and find the temperature distribution based on the a novel derivative method. Perforated with rectangular section and different angles of inclination was considered. Signum Function is used for modeling the variable heat transfer area. Set of parameters to handle the conduction and convection area were calculated. Degenerate Hypergeometric Equation (DHE) was used for modeling the complex energy differential equation and then solved by Kummer's series. In the validation process, Ansys 16.0-Steady State Thermal was adopted. For the calculation process, two models (I & II) were considered. The high agreement of the validation results about (0.25%) leads to the big reliability of the presented model. The results show the improvement of the temperature difference and heat transfer ratio according to the increase of the inclination angle and perforated size. Improved of Heat transfer ratio is ranging from 13% to 50%.