The present invention relates to a method of estimating the position of a mobile node in a wireless sensor network using a passive mode OWR method. The method includes: estimating frequency offsets of anchor nodes and a mobile node; allowing the anchor nodes to sequentially transmit ranging frames; allowing the mobile node to receive the ranging frames and to estimate the difference between the reception times of signals from two anchor nodes; and applying the estimated difference between the reception times of the signals to time difference of arrival (TDOA) to estimate the position of the mobile node. According to the above-mentioned structure of the present invention, a plurality of mobile nodes can estimate their positions with a minimum number of ranging frame transmissions, without using a separate network synchronization unit. In addition, it is possible to easily construct a wireless sensor network for position recognition, and rapidly and accurately perform distance estimate using an OWR method.