To solve the single-observer passive location estimation using multiple illuminators of opportunity, a time difference of arrival(TDOA) location algorithm based on maximum likelihood is proposed. Firstly, according to the functional relationship between the TDOA measurements and the target location, the likelihood function of the target location is constructed. Then Newton′s method is applied to obtain the global maximum of the nonlinear likelihood function and determine the target position. The least squares solution of the target location is derived and used as the initial guess of the Newton′s method. Finally, the theoretical error and the Cramer Rao Lower Bound (CRLB) are also derived and proved to be equal. Simulation results demonstrate that the proposed algorithm outperforms existing algorithms and achieves the CRLB at moderate noise level. Moreover, from the geometric dilution of precision figure, the influence of target position, illuminator number and position on the localization accuracy is analyzed.