Abstarct: More than 70% of the earth's surface is filled by water. Therefore, identifying the water environment is important. One of the systems that are used for this purpose is Underwater Wireless Sensor Networks (UWSN). These networks are distributed in the water environment and identify events. But, to determine the location of the event, we need to know where the event detector node is located on the network. Therefore, the positioning of underwater sensor networks becomes important. Different models for determining the position of nodes in the network are presented, each of which models behave according to a particular algorithm. One of these algorithms is the TDOA algorithm. Different methods are available to estimate TDOA. In the present study, the approach baxsed on Generalized Cross-Correlation (GCC) has been proposed to estimate TDOA. The proposed method is called the Correlated Modified Maximum Likelihood (MMLC) method, which is a combination of the modified maximum likelihood (ML) and phase-transform (PHAT) methods. The proposed method, in addition to being able to estimate in desirable conditions, also performs well in undesirable conditions and has a better estimation of the target position than other methods. After estimating TDOA using the above methods, we also investigated the target position baxsed on the LS, WLS and CRLB methods. According to the results, the proposed method has a better effect on the more accurate estimation of the target position.