Method for preparing nano capsule

The invention discloses a method for preparing a nano capsule. The method comprises the following steps: preparing a wall material solution, preparing emulsifiers, emulsifying a core material and forming the nano capsule. According to the method, two emulsifiers, namely dehydrated sorbitol monostearate (Span60) and polyethyleneglycol dehydrated sorbitol monooleate (T80) are selected and compounded according to different ratios so as to obtain the emulsifiers that the HLB (Hydrophile Lipophile Balance) values are respectively 11 to 15, and by controlling the HLB values of the emulsifier in the core material emulsification process, the particle size and the particle size distribution index PDI of the nano capsule are reduced, and the overall property of the nano capsule is improved. Tests by using a dynamic laser spectrum scattering instrument show that the average particle size of the prepared tuberose sustained-release nano essence capsule is 110.7nm, the particle size distribution coefficient is 0.156, and t