Kinesin is one of the most important linear motors for intracellular transport. It has two main features. One is its persistence: at least one head is attached to the microtubule during stepping, so that it can move a long distance before detaching. Another feature is the tight mechanochemical coupling: it consumes one adenosine-triphosphate for each step. Therefore, there should be a mechanism responsible for the coordination of the two heads to achieve the high persistence and tight coupling. The underlying mechanism is the mechanochemical coupling, which is the basic issue for all chemical-driven molecular motors. Owing to the developments of single-molecule experiments and molecular dynamics simulations, a breakthrough in the coupling mechanism has been made in recent decades. In this article, we review the progress of the relevant researches from the perspective of kinematics, energetics, coordination of two heads and force generating mechanism. We also present a personal perspective on the future studies of kinesin.