Abstract: The waterborne ultrafine carbon black dispersion which was used in dope dyeing for Lyocell fiber were prepared by using direct dispersing method and emulsion polymerization method，respectively，and the particle size which obtained with different method and their dispersion stabilities in the N-methyl morpholine-N-oxide (NMMO) solution were further investigated．Experimental results revealed that emulsion polymerization method was suitable for preparation of nanoscale waterborne carbon dispersion．The centrifugal and antitemperature stabilities of encapsulated carbon in NMMO solution were obviously better than dispersing carbon．The apparent viscosity of NMMO solution decreased when added some encapsulated carbon, the more amount of encapsulated carbon added，the lower viscosity of NMMO solution was．