A magnetic separator, which consisted of permanent magnet drum, separation chamber and scraper blade, was manufactured for efficient microalgae harvesting. The harvesting efficiency of Chlorella ellipsoidea cells reached more than 95% within forty seconds in each batch operation of microalgae harvesting. In the continuous operation of microalgae harvesting, the harvesting efficiency decreased with increasing the liquid flow rate through the separation chamber and remained more than 95% at the liquid flow rate less than 100 mL/min. The developed magnetic separator together with functional magnetic nanoparticles provided a promising method for efficient microalgae harvesting in practice. (C) 2014 Elsevier Ltd. All rights reserved.