A　method　for　preparing　samarium-cobalt　compound　nanoparticles　having　an　adjustable　composition　and　particle　size,　　belonging　to　the　technical　field　of　nano　permanent　magnet　material　preparation.　A　samarium-cobalt　alloy　prepared　by　elemental　samarium　and　cobalt　metal　smelting　is　used　as　the　raw　material　to　prepare　various　samarium-cobalt　compound　nanoparticles　with　an　average　particle　size　of　less　than　100　nanometers　and　being　adjustable　such　as　Sm2Co7,　　SmCo5,　　SmCo7,　　Sm2Co17　and　the　like　by　means　of　evaporative　condensation　manners　such　as　in-situ　formation　and　in-situ　collection　under　the　anaerobic　conditions　of　high　purity　inert　gas　protection.　This　method　has　a　simple　process　and　a　short　production　cycle,　　and　provides　high-purity　inert　gas　protection　throughout　the　whole　manufacturing　process,　　avoiding　oxidation,　　providing　products　having　a　good　comprehensive　magnetic　performance.