The invention relates to water dispersion type carbon nano-tube freeze-dried powder and a preparation method thereof, and the problem of actual needs in pharmacy taking carbon nano-tubes as medicament carriers can be effectively solved. The technical scheme for solution is as follows: the water dispersion type carbon nano-tube freeze-dried powder is prepared by the carbon nano-tubes, a surface active agent and a freeze-drying protecting agent, wherein the weight ratio of the carbon nano-tubes with the surface active agent is 1:2-10 and the weight ratio of the carbon nano-tubes with the freeze-drying protecting agent is 1:1-10. The preparation method comprises the following steps: placing the carbon nano-tubes in water solution of the surface active agent, performing ultrasonic treatment by a cell disruption instrument, further performing the ultrasonic treatment by an ultrasonic washing machine, centrifugating and sucking supernatant liquid to obtain the water dispersion type carbon nano-tubes; adding the freeze-drying protecting agent into the water dispersion type carbon nano-tubes, oscillating, uniformly stirring and then freezing; and taking out the frozen water dispersion type carbon nano-tubes and rapidly placing into a freeze-drying machine for freeze-drying. The water dispersion type carbon nano-tube freeze-dried powder is strong in water dispersion. The preparation conditions are easy to meet, sources of raw materials are abundant, the cost is low, the stability is strong, and the storage life is greatly prolonged.