The invention relates to the technical field of polyurethane elastomers, in particular to a polyurethane microporous foaming film for persistent antibacterial central venous catheters and a preparation method of the polyurethane microporous foaming film. The polyurethane microporous foaming film for persistent antibacterial central venous catheters is obtained by modifying polyurethane film with an active medium and a bacteriostatic agent under the action of a supercritical foaming gas; wherein the dosage of the active medium is 0.1-5% of the mass amount of the polyurethane film; the use amount of the bacteriostatic agent is 0.1-5% of the mass amount of the polyurethane film; the polyurethane film is prepared from the following raw materials: a polyether polyol, a diisocyanate, a small molecular chain extender, a nano filler and a catalyst. According to the polyurethane microporous foaming film for persistent antibacterial central venous catheters, the surface of the polyurethane microporous foaming film is of a fine rough structure, the situation that an existing central venous catheter is prone to falling off from the great vein of human body is avoided, the long-acting antibacterial effect is achieved, and the problem that an existing material is poor in continuous antibacterial effect is solved; the invention also provides a preparation method of the polyurethane microporous foaming film.