SmCo5 alloy was prepared via direct calciothermic reduction using anhydrous samarium fluoride (SmF3) as raw material and cobalt as inducer. Results of the thermodynamic calculation show that the direct reduction of cobalt-induced SmF3 for preparing SmCo5 alloy is feasible. An alloy with 33.89 wt％samarium and a yield of 96.45％ were achieved under the optimal conditions of 10％ and 20％ excess of SmF3 and calcium over the stoichiometry, respectively, and 1450 C for 4 min. The X-ray diffraction results show that the reduction products are SmCo5 alloy and CaF2. The scanning electron microscopy micrograph of the SmCo5 alloy ingot exhibits a distinct dendritic morphology composed of samarium and cobalt. The X-ray photoelectron spectroscopy shows that the atomic ratio of samarium to cobalt is approximately 1:5 and both elements demonstrate zero valency (Sm0, Co0). The magnetic properties measurement of the SmCo5 alloy melt-spun ribbon shows the remanent magnetization Br = 0.59 T, intrinsic coercivity Hci = 345.82 kA/m and maximum magnetic energy density (BH)max = 42.20 kJ/m3. These results may be helpful for the development of novel valence-variable rare-earth alloys.