By analyzing the classical algorithm for the three-dimensional(3-D) tri-station Time Difference Of Arrival(TDOA) location, the reasons to produce ambiguity and non-solution were discussed. The correlation of the distribution of non-solution area with the placement of stations, stations site error and TDOA error was analyzed. Some methods to solve the problems of ambiguity and non-solution were presented. In the practical application, the priori information of targets should be used adequately. The methods to solve the problems of ambiguity must be used well to reduce complexity and enhance operation efficiency. Meanwhile, the distribution of stations should be optimized to make the target area to be out of the non-solution area.