The invention belongs to the technical field of a nanometer material, and specifically relates to a technical method for surface sizing treatment for carbon nanotubes. The sized carbon nanotubes can be used as a reinforcement for epoxy resin composites cured with an amine curing agent. The method comprises the following technical steps: step I, adding amino-functionalized carbon nanotubes in an optimal sizing agent solution, and performing ball-milling to obtain an uniform liquid mixture; step II, performing filtration to remove the redundant sizing agent solution from the mixture obtained from the step I and performing vacuum drying; and step III, performing secondary ball-milling to dried carbon nanotubes, and screening the ball-milled carbon nanotubes with a rotary vibrating screen to obtain the sized carbon nanotubes with different sizes. The sized carbon nanotubes can be easily dispersed in an epoxy resin matrix, are beneficial for surface infiltration of the epoxy resin, and has an obvious reinforcement effect on an epoxy resin matrix cured with an amine curing agent. The method is simple in process and easy for actual production and application.