A simple and effective method was proposed to prepare uniform surface-imprinted nanoparticles. This strategy was carried out by introducing vinyl groups to the surface of silica beads by a one-step modification, followed by copolymerization of functional monomers via reversible addition–fragmentation chain transfer (RAFT) precipitation polymerization. Owing to the intrinsic advantages of controlled/living polymerization and surface imprinting technology, the resultant RAFT surface-imprinted nano-sized polymers (RAFT-SINPs) demonstrated spherical shaped particles with excellent monodispersity, and improvements in imprinting efficiency and mass transfer in comparison to molecularly imprinted polymers (MIPs) prepared by traditional precipitation polymerization. Recoveries of 93.4% and 79.8% were achieved by one-step extraction when RAFT-SINPs were used for the preconcentration and selective separation of atrazine in spiked corn and lettuce samples, respectively. These results provided the possibility for the separation and enrichment of atrazine from complicated matrices by RAFT-SINPs.