Sintered Nd-Fe-B and Sm-Co composite magnets were prepared by adding calcium fluoride and their properties were investigated.Experimental results show that the electrical resistance of the sintered Nd-Fe-B magnets with CaF₂ increased,but their magnetic properties decrease to some extent.The magnetic properties of the sintered Sm-Co magnet with CaF₂ decreased seriously due to the oxidation during the preparation process.The scanning electron microscopy results show that there did not form 1:5 phase and 2: 17R phase in microstructure of the sintered Sm-Co / CaF₂ composite magnet.The CaF₂ was distributed in the grain boundary attached to the Nd-rich phase and has a little effect on the microstructure of sintered Nd-Fe-B/CaF₂ composite magnet.It is a way to increase the electrical resistance for the sintered Nd-Fe-B magnet by adding CaF₂.