A method for making colloidal nanocrystals includes the following steps: dissolving a nanocrystal powder in an organic solvent, and achieving a solution A of a concentration of 1-30 mg/ml; dissolving a surfactant in water, and achieving a solution B of a concentration of 0.002-0.05 mmol/ml; mixing the solution A and the solution B in a volume ratio of 1: (5-30), and achieving a mixture; stirring and emulsifying the mixture, until an emulsion C is achieved; removing the organic solvent from the emulsion C, and achieving a deposit; then washing the deposit with deionized water, and achieving colloidal nanocrystals. The present method for making colloidal nanocrystals is economical and timesaving, and has a low toxicity associated therewith. Thus, the method is suitable for industrial mass production. The colloidal nanocrystals made by the present method have a readily controllable size, a narrow size distribution, and good configuration.