We present the catch and release technique with DNA using imidazolium-presenting nanoparticles via anion exchange. The imidazolium-tethered superparamagnetic iron oxide (SPIO) was prepared and the binding behavior to DNA was investigated. Accordingly, when the imidazolium cation forms an ion pair with the hydrophilic anion such as chloride, DNA can be absorbed onto the modified SPIO. In contrast, by anion exchange to hydrophobic anion such as TFSA, the binding affinity greatly decreased, resulting in the release of DNA. Moreover, the release efficiency can be improved by introducing a silica layer at the surface of SPIOs. Finally, the catch and release with DNA was accomplished under mild conditions.