A hinge structure includes a main support including a sliding groove disposed therein; a limit support rotationally connected to the main support via a straight shaft disposed in the sliding groove, and a limit groove is disposed at one side of the limit support; a sub support connected to the limit support via a crank shaft, wherein the sub support is sleeved on the crank shaft, a crank sliding block is disposed at one end of the crank shaft and in the limit groove; and a shaft sleeve; wherein when the main support rotates relative to the sub support, the straight shaft slides in the sliding groove and the crank sliding block slides in the limit groove. A folding mechanism and a mobile terminal are also provided.