An accurate and efficient computational method is proposed for the time-optimal switching control problem of non linear systems. The method is based on spectral collocation technique using the Legendre-Gauss nodes. Spectral method is used to discretize the problem in a sequence of time subdomains separately and form a non linear programming problem. By solving this NLP problem, the optimal control in each subdomain and the joining times of the subdomains will be obtained simultaneously. The method is computationally attractive and applications are demonstrated through illustrative examples.