A spring hinge base structure is provided, including: a body, having a first tube and a first plate portion; locking units each having a cover and an engagement member, each engagement member being engaged within the cover, two of the locking units being connected to opposite ends of the first tube; an elastic element, engaged with the two locking units; a second plate portion; and a shaft, disposed through the respective cover and respective engagement member, wherein the second plate portion is integral and rotatably movable together with one of the locking units by a bump component and abutted between the second plate portion and one of the locking unit.