A new Monte-Carlo （M-C） curve fitting algorithm which is more stable than other iterative fitting algorithms is presented, and it is used to improve the unsatisfactory fitting results of the data of electron momentum spectroscopy（EMS） experiment due to the serious overlap of adjacent peaks of orbital energy resulting from the poor energy resolution. The VB program of this method has been compiled. The results of EMS data of CF2Br2 using the M-C program is compared with the one using PeakFit software, which is based on Levenberg-Marquardt algorithm, and shows much better effect. Furthermore, the ordering of the four outer valence orbitals（4b2, 2a2, 4b1 and 6a1） has been assigned, which suports the conclusion of the Hartree-Fock and OVGF calculation and revises the assignment using PES.