Objective: To prepare a Wrapped liquid fluorocarbon, which can carry liver cancer therapeutic genes and has folic acid molecular targeting nano-scale ultrasound molecular probe, and to study its basic characteristics and ultrasound imaging capability. Methods: Pegylated imine was used to connect folic acid (Fa) molecules on the surface of PLGA to prepare targeted membrane material (PLGA-Fa), then PFP-loaded nano-scale targeted ultrasound contrast agent was prepared by double emulsification method, and after incubation with polylysine, positively charged cations were formed on the surface, and plasmids (PLGA-Fa-PFP-S) were loaded on the surface of nanoparticles by positive and negative charge adsorption. The nanoparticles were treated by heating and LIFU irradiation respectively. The phase change was observed under a microscope and the Image display effect in vitro was observed in contrast-enhanced ultrasound mode. Results: Nanoscale targeted ultrasound contrast agent (Fa-PLGA/PFP/S) loaded with plasmid and PFP was successfully prepared. The nanoparticles were uniform in size, round in shape, good in dispersibility, with a diameter distribution of 200.5nm and an average potential of +37MV. When heated to 50 degrees and irradiated with LIFU 5th stage radiation for 5 minutes, more nanoparticle phase changes were visible under the microscope, and imaging was also visible under ultrasound contrast mode.In addition, folate - free non-targeted contrast agents were prepared by double - emulsion method，they were incubated with liver cancer cells HepG2 respectively to observe their target-seeking ability. Conclusion: A nano-scale targeted ultrasound contrast agent (Fa-PLGA/PFP/S) with plasmid and PFP was successfully prepared in this study. The nanoparticles can be used for ultrasound contrast imaging.It was also observed that the targeted contrast agent has obvious targeting effect in cell experiments.