A power source terminal structure includes an insertion terminal and a docking terminal. The insertion terminal has a main body and a contacting portion. The contacting portion is formed by extending from one end of the main body. The contacting portion is provided with a first protrusion. The docking terminal has a base and two elastic arms. The two elastic arms clamp the main body. The base is provided with a second protrusion opposite perpendicular to the first protrusion. The second protrusion contacts the first protrusion. Via this arrangement, the contact area between the insertion terminal and the docking terminal can be increased, and the reliability of the connector for transmitting the electric current and signals can be increased. Thus, the electric current is more stable.