BACKGROUNDAg nanoparticles (AgNPs) were plant-mediated synthesized in a microfluidic chip at room temperature. The formation process and particle size distribution (PSD) were numerically simulated by a multiphase flow model incorporating reactive kinetics and a population balance equation (PBE). The influences of flow rate on particle size distribution were demonstrated in detail by both experimental research and simulative analysis. RESULTSIt was found that there was an identified microfluidic chip flow rate distinguishing the influences into two stages. At the first stage, mixing efficiency was the restrictive factor while residence time was the restrictive factor at the second stage. CONCLUSIONIt has been concluded that the identified flow rate is the balance between mixing efficiency and residence time at which the average particle size can achieve the maximum value. (c) 2017 Society of Chemical Industry