Friction stir welding is a process of solid-state welding for jointing between two metal parts without using a heat source. It just depends on friction between the tool and the metal parts. In addition, it is considered a clean and inexpensive welding process because it does not require welding wires. The products have high mechanical properties after the welding process. In this paper, the effective cone ratios of welding tools were numerically investigated using FEM software for joining two AA7075 plates. Different four-cone ratios were used to show the effective tool geometry for effective nugget zone temperatures. A linear velocity, rotation speed, friction coefficient, and axial force were used as comparing tools to find out the effective cone ratios. Results show that a lower cone ratio has effective nugget zone temperature.