Abstract:【Abstract】 Extensive application of ultrasound contrast agents have remedied the limitations of conventional ultrasound and improved the accuracy of diagnosis. However, the resolution of ultrasonic image and sensitivity remain unsatisfactory. With the development of ultrasound molecular probes, combination of multifunctional ultrasound contrast agents with different imaging modalities may further improve diagnostic and therapeutic processes by complement each other's advantages. Therefore, it has become the focus of ultrasound molecular imaging research. The multifunctional ultrasound contrast agents included targeted ultrasound contrast agent, multimodal contrast agent and theranostic agent based on ultrasound imaging. When combined with the advantages of Xray computerized tomography (CT), magnetic resonance imaging (MRI), positron emission tomography (PET) and fluorescence imaging, the multifunctional ultrasound contrast agents could be used for visualization of cellular function and tracking of molecular processes through targeted cells and/or molecules in vivo, which reflect intuitively the physiological and pathological changes. The multifunctional ultrasound contrast agents have broad application prospect, they may improve the accuracy of diagnosis and also play a role in therapeutic process by carrying genes or drugs.