Dual-satellite passive location system is a passive location method based on time difference of arrival and frequency difference of arrival. In order to improve the positioning accuracy, the position differential and pseudo-range differential method of satellite navigation system is used to correct the positioning error of this system, and the positioning accuracy after the correction is about 5 km. But there is one problem when we use the method. That is, basing on the result of positioning error distribution, positioning error in the band about ±100 km in the direction of the line between the two satellites using time difference of arrival and frequency difference of arrival positioning is very big, and positioning accuracy is very poor or the emitter can’t be positioned in that area, which is called blind zone. In order to solve the difficult positioning problem in the blind zone, the reason for the positioning blind zone is given and a new method of multi-epoch time difference positioning is proposed. The results of solving method and simulation show that high positioning accuracy can be obtained by using the multi-epoch time difference method for the positioned emitter in the blind zone, which can effectively solve the problem of blind zone in positioning area.