The magnetic properties and loss characteristics of ferromagnetic materials in 300K and 77K environments were investigated by means of simulated impact method. In ferromagnetic materials DT4, 1J22, 2Cr13 and amorphous FeSiB alloy as the research sample, the results of the study show that in nitrogen environment, saturation magnetic induction intension of DT4, 1J22, 2Cr13 and amorphous FeSiB were slightly increased, the saturation magnetic induction intension of FeSiB increases to a maximum of 5.3%; The coercive force of DT4, amorphous FeSiB and 2Cr13 increases greatly, and the coercive force of DT4 increases by 106%, while the 1J22 decreases by 1.7%; When the frequency is 50Hz, the loss of DT4 in liquid nitrogen environment increases sharply compared with that at normal temperature. The loss of amorphous FeSiB and 2Cr13 increases slightly compared with the normal temperature, while the loss of 1J22 varies little. Finally, the magnetic field calculation of the magnetron sputtering cathode with superconducting coil excitation is taken as an example. Under the same structure of iron core, the maximum value of the horizontal component of magnetic field is 2284Gs with 1J22 as the core of the magnetron sputtering cathode. Compared with 2Cr13 as the iron core, the maximum value of the horizontal component of magnetic field increases by 9.2%. The study of low temperature magnetic properties of ferromagnetic materials can provide reference for the design of magnetic circuit of superconducting electromagnetic equipment.