We consider a gradient flow generated by a complex Hessian functional which is
defined on compact Kähler manifolds. By setting up the a priori estimates of the
admissible solutions, we prove the long-time existence of the solution to the flow and
its convergence. Thus we show the functional admits a local minimal point in the
space of admissible functions. As its application, we show the solvability of a class of
complex Hessian equations.