The present invention relates to a system and a method for location determination using time differences. The method of the invention comprises the steps of: transmitting a transmission signal by using a directional transmitter rotating at an angular velocity, the transmission signal comprising a transmission identification and the transmitting time; receiving the transmission signal by using an omnidirectional transceiver, and adding a personal identification to the transmission signal to be a response signal; transmitting the response signal; receiving the response signal by using an omnidirectional receiver and recording the receiving time; and calculating the location of the omnidirectional transceiver corresponding to the directional transmitter according to the difference between the receiving time and the transmitting time. By utilizing the system and the method of the invention, the corresponding location of the omnidirectional transceiver can be calculated accurately without disposing a lot of sensors in the space, and the system of the invention need not be reconfigured for new environments. Therefore, the conventional problems of high installation cost and complicated settings can be improved.