Although the traditional five-bucket phase-shifting algorithm possesses excellent accuracy, it isn't used in the practical length measurement because of the strict conditions of equal step length of phase shifting. Based on two-beam interference principle, a corrected five-bucket phase-shifting algorithm which possesses high accuracy with an arbitrary phase step in range of 10 nm is present. With the numerical simulation, it shows that the accuracy of the corrected algorithm is better than 0.001 phase period when the measuring error of the phase step is 1 nm and the measuring error of the signal is 0.1%, besides that, this algorithm does not need accurate equal step length of phase shifting. With higher reliability and higher accuracy, the corrected five-bucket phase-shifting algorithm is very valuable for the precision length measurement.