Remote Radio Unit (RRU) is the main part of the 5G base station that has a great size with a high density of chipsets and be operated with significantly high temperature. This paper introduces an optimization protocol of geometric parameters of heat sink on thermal dissipation for RRU 5G 8T8R operation at 2600MHZ. Firstly, the heat sink is calculated by analytical method with minimization of entropy energy. In the next step, two more prototypes of heat sink are proposed to consider their performance on thermal dissipation. The simulation results demonstrated that in general, the heat sink with V-shaped fin has the better performance on thermal dissipation in comparison to conventional models such as in-line arrangement fin heat sinks. An optimal heatsink for RRU 5G have been simulated by FEM method considering different working conditions such as wind speed and high attitudes.