This paper considers the finite time stability of nonlinear systems. By using the method of function construction
and variable substitution, a new sufficient condition of finite time stability is derived for nonlinear system. This condition is
less conservative than the existing results. Furthermore, it is applied to analyze the finite time stability of a class of uncertain
nonlinear systems. A sufficient condition for finite time stability is given by the method of constructing Lyapunov function.
A numerical example shows the effectiveness of the theoretical results.