Amorphous alloy Fe73.5Cu1Nb3Si13.5B9 was treated by low frequency pulsating magnetic field. The microstructure of the amorphous alloy sample was analyzed by M?ssbauer spectroscopy and TEM. The results show that the initial nano-crystallozation occurs in the ample during the pulsating magnetic field treatment at room temperature. By means of the alternating gradient magnetic meter and self-made magnetostrictive coefficient measuring instrument, coercive force Hc, saturation magnetization strength Ms, initial superconducting rate μi, and magnetostrictive coefficient λs of the samples were measured before and after low frequency pulsating magnetic field treatment. Results show that the overall μi increases after low frequency pulsating magnetic field treatment, while Hc and λs are smaller than those of the as-prepared amorphous alloy. It indicates that low frequency pulsating magnetic field treatment can optimize comprehensive soft magnetic properties of amorphous alloys, and the optimization degree of soft magnetic properties is relevant with the parameters of plused magnetic field. The soft magnetic properties of the sample reach the best when the pulsating magnetic field strength Hp=250×79.6 A/m, pulsating frequency f =30 Hz and disposing time t=4 min.