Abstract: A foldable trampoline includes a frame consisting of multiple frame sections, a jumping bed, and a plurality of legs connected to each joint of two adjacent frame sections. At least two knuckle mechanisms are provided at two opposite joints of the frame sections. Each knuckle mechanism includes two clamp brackets that are fixedly connected to two adjacent frame sections at their opposed ends. Each clamp bracket has two spaced arms that forward extend beyond the end of the frame section by a predetermined length and then turn downward to form two lug portions. The lug portions of the two clamp brackets are overlapped and pivotally connected to each other via a shaft pin extended therethrough. The shaft pin also extends through the leg located at the joint, so that the two adjacent frame sections may be pivotally turn about the shaft pin without the need of dismounting the leg thereat.