A phase shift extraction algorithm based on the special points in two-step generalized phase-shifting interferometry is proposed. This algorithm searches the special points that meet specific requirements and calculates the phase shift via the latter′s relationship with these special points. It is divided into two modes according to whether the intensity distributions of the two interference beams are recorded or not. Theoretical analysis, computer simulation and experimental verification are carried out. Experimental results show that this algorithm reaches the same level of other algorithms in speed and accuracy. Moreover, when the interferogram′s fringe number is less than one, a better phase shift extraction accuracy can be obtained.