The invention provides a novel Irinotecan carrier which is circulating nano liposome and a novel preparation method thereof which is an ethanol injection-ammonium sulfate active medicament-loading method. The preparation process comprises: a, dissolving a lipid material for forming the liposome in ethanol to prepare solution; b, dissolving a polyethylene glycol compound in solution of ammonium sulfate to prepare a hydration medium; c, injecting solution obtained by the step a into the hydration medium obtained by the step b with stirring in a water bath, stirring at a constant temperature for a certain period under a condition of introducing N2 to form circulating blank liposome; d, dialyzing the blank liposome obtained by the step c in physiological saline; and e, adding solution of Irinotecan into the blank liposome, regulating the pH value of an external phase, and performing incubation and medicament loading at a certain temperature to obtain the Irinotecan circulating nano liposome. The process is simple, the particle size is 80 to 150 nanometers, the coating rate is over 95 percent, the sterile preparation can be obtained easily, and an industrialization requirement is met.