We studied the existence of homoclinic orbits and the homoclinic bifurcations in planar piecewiselinear system. The existence of homoclinic orbit in this system can be divided into two cases, one is a system formed by a visible saddle point and a visible focus (or a center), the other is a system formed by the coincidence of the original point and two nodes with inverse stability. In this paper, we provided the necessary and sufficient condition for the existence of homoclinic orbit, and then analyzed the homoclinic bifurcation.