this invention provides molecularly imprinted polymer nanoparticles compatible with biological samples , and in particular pure biological samples and a preparation method thereof . said molecularly imprinted polymer nanoparticles have a crosslinking degree exceeding 50 %, a particle diameter of 10 to 500 nm , hydrophilic polymer brushes on its surfaces and can be prepared by introducing appropriate hydrophilic macromolecular chain transfer agents into reversible addition - fragmentation chain transfer precipitation polymerization systems through the one - pot synthesis . the preparation method is simple , features a broad range of application and yields a pure product . the obtained hydrophilic molecularly imprinted polymer nanoparticles have prospects for a wide range of application in biological sample analysis , medical clinical immune analysis , food and environmental monitoring , biomimetic sensors , etc .