The　oil-based　Nd-Fe-B　sludge　waste　was　directly　recycled　to　single-phase　Nd2Fe14B　powders　via　the　combination　of　purification　and　modified　Ca-reduction　reaction　method.　The　impurities　and　organics　in　the　purified　Nd-Fe-B　sludge　waste　were　greatly　reduced,　reducing　calcium　consumption　in　the　subsequent　reduction　and　diffusion　(RD)　process,　thereby　reducing　the　cost.　By　further　optimizing　the　Ca-reduction　diffusion　parameters,　especially　the　mass　ratio　of　CaCl2　and　KCl,　where　the　liquid　CaCl2,　along　with　the　gaseous　KCl　provide　conditions　for　sufficient　and　uniform　Ca-reduction　reaction,　high-property　Nd-Fe-B　magnetic　powders　with　good　dispersion,　uniform　particle　sizes,　and　excellent　orientation,　were　successfully　obtained.　Using　the　mixed　diffusion　medium　of　CaCl2　and　KCl　with　a　mass　ratio　of　1:1,　the　room-temperature　magnetization　of　the　recycled　Nd-Fe-B　powders　was　increased　to　157　emu/g　at　3　T-magnetic　field,　which　was　about　28　%　higher　than　that　of　the　original　sludge.　The　contents　of　carbon,　hydrogen,　and　oxygen　in　the　recycled　magnetic　powders　were　significantly　reduced　from　6.8,　1.8,　and　5.9　wt%　to　0.1,　0.19,　and　0.56　wt%,　respectively.　In　addition,　the　uniform　grain　size　with　X-50　=　3.6　mu　m　and　good　distribution　greatly　improved　the　orientation,　which　can　be　beneficial　to　the　preparation　of　the　bonded　or　sintered　Nd-Fe-B　based　magnets.　The　reasons　that　CaCl2-KCl　mixed　diffusion　medium　can　lead　to　well-dispersed,　uniform　recycled　powder　with　high　magnetization　arise　from　a　combination　of　factors　for　improving　the　liquid　phase　reaction　environment　and　the　gaseous　KCl　to　prevent　agglomeration　and　inhibit　particles　merging　or　growth.