Abstract: Phytosteron in achyranthes bidentata was separated and enriched by solvent floatation and the optimum conditions for which (including choice of solvent,pH of solution,flow-rate of nitrogen and time of floation) were studied systematically.The optimized conditions found were as follows: ① n-butanol was chosen as floatation solvent;② suitable acidity of solution was found to be pH 5;③ optimal flow-rate of nitrogen was 40 mL·min-1;and ④ 80 min was taken as the time for the floatation.Efficiency of the solvent-floation was evaluated by measuring the absorbance of the butanol phase at 247 nm for estimation of floatation rate of phytosteron.As compared with the solvent extraction method,the solvent floatation method for separation and enrichment of phytosteron was proved to have higher efficiency and to take less time in the separation process.