For navigation using X-ray pulsars, both technique investigation and simulation were based on the X-ray pulsar signal. But practically, the observation data was unable to confirm the exact value or the analysis of validation of navigation algorithm. Therefore, it was necessary for simulation algorithms to reconstruct X-ray pulsars. Based on the fact that the arrival of photons possess non-homogeneous poisson random process, the model of the signal of X-ray pulsars was built, and the epoch folding algorithm for pulse profile construction was presented. Two existed simulation algorithms were presented. A new numerical simulation algorithm based on the reconstruction of photon TOAs (time of arrivals) was derivated from distributive function and its inverse function. To avoid approximating in the two algorithms, the derivated algorithm employed the pulse profile fitted by piecewise linear function. The signal of pulsar PSR B0531 +21 was simulated, and chi-square goodness-of-fit-test was utilized to demonstrate that the simulated TOAs complied with the poisson distribution. Comparison was implemented among the new algorithm and the existed two algorithms. Simulation result indicates that the new algorithm is superior to the existed two algorithms in photon counts and pulse profile error. Observed pulse profiles approaches to the standard template profile as observation time increases, which demonstrate that the simulation algorithm is feasible, and the X-ray pulsar signal can be reconstructed effectively. 