Poly(lactic-co-glycolic)acid(PLGA)is a kind of biodegradable polymer materials.It has good safety,biocompatibility,and stability.As a new kind of high moleculer polymer ultrasound contrast agent,PLGA nanoparticles have many good charaters such as good ultrasound imaging enhancement,small and tight distribution.PLGA nano-technology is widely used in drug delivery system,gene therapy,disease diagnosis,tissue engineering,vaccine development and so on.This article reviews the preparation of PLGA nanoparticles,its nature and clinical applications.