A load connecting mechanism includes a mounting portion, a contact portion, and a force-exerting portion. The mounting portion is configured to mount the load connecting mechanism to a power source and a load, respectively. The contact portion is disposed on the mounting portion and includes two slidably coupled contact faces. The force-exerting portion is configured to provide a force to the contact faces in an axial direction of the power source to make the contact faces closely slidably couple to each other. Through the slidable coupling relationship between the contact faces, power of the power source is progressively transmitted to the load and finally drives the load to rotate in synchronization with the power source. The present invention further provides a motor driving assembly and a fan. The mechanism can satisfy the needs of bidirectional rotation of a load such as a fan and of large startup torque.