Carbon nanofibers ( CNFs ) are easy to aggregate together. To solve this problem, CNFs were purified by high temperature treatment and stable homogenous CNF suspension was obtained by using methylcellulose ( MC) as a surfactant. The purification of CNFs and the homogenous CNF suspension were investigated by differential thermal analysis, thermo-gravimetric analysis, ultraviolet absorbency and zeta potential. Furthermore, the isotherm adsorption of MC on CNFs and surface tension of CNFs in MC solution were studied. The dispersion mechanism of CNFs in aqueous MC solution was discussed. The results showed that the zeta potentials of CNFs increased progressively from-15.4 mV to 0, and the surface tension decreased from 38.87 mN/m to 36. 54 mN/m. The isotherm adsorption of MC showed an adsorption platform, and the isotherm reached the saturation plateau at MC concentration of about 0.4 g/L. The optimum MC to CNFs ratio of 2∶1 by mass was required to achieve dispersions with maximum achievable dispersion of CNFs in the aqueous MC solution.%为了研究纳米碳纤维（ CNFs）在水溶液中的分散情况，对其进行高温纯化处理，以甲基纤维素（ MC）为分散剂，制备分散良好的CNFs悬浮液．采用差热分析（ DTA）和热重分析（ TGA）研究了高温处理对CNFs的影响，通过测定悬浮液的紫外可见光吸光度、等温吸附曲线、zeta电位及表面张力等方法研究了MC对CNFs分散性能的影响，并讨论分析了MC对CNFs的分散机理．结果表明：MC的加入使CNFs悬浮液的zeta电位由-15．4 mV升至0，表面张力由38．87 mN/m降至36．54 mN/m；等温吸附曲线表明MC在CNFs的表面为“单阶段吸附”，当MC的质量浓度达到0．4 g/L时，MC在CNFs表面饱和吸附；当CNFs达到最佳分散状态时，MC与CNFs的质量比为2∶1．
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