Accurate Time Delay Estimation (TDE) is a prerequisite for sound source localization technology based on Time Difference Of Arrival (TDOA). Compared with other TDE algorithms, the Generalized Cross Correlation (GCC) algorithm has been widely used due to its low computational complexity and implementation simplicity. GCC time delay estimation algorithm uses different weighting functions to suppress noise and other interference in different noise conditions. This work first presents microphone array model and GCC algorithm. Then, an improved algorithm proposed in the study is elaborated in view of the disadvantages of GCC algorithm. Furthermore, GCC algorithm to partial weighting functions is simulated using MATLAB under different Signal-to-Noise Ratio (SNR) conditions. The advantages and disadvantages of these weighting functions are analyzed by comparing the performance of time delay estimation and the accuracy of sound source localization.