According to established Lorenz curve equation，this paper uses particle swarm optimization algorithm to estimate parameters of the equation; Then it calculates the Gini coefficients of Chinese urban and rural from 2002 to 2011 by the fitted Lorenz curve .After that it computes Chinese overall Gini coefficient by weighting method. The final conclusion show that particle swarm optimization algorithm can effectively estimate parameters of Lorenz curve equation; And the tendency of the Gini coefficients from 2002 to 2011 corresponds to the opinion of most scholars. So it provides a reliable and effective method for parameters estimation of Lorenz curve.