Copper and cobalt usually coexist in the leachate of waste lithium ion batteries, sea nodules and other copper ore or by-product. Conventional methods for the separation of copper and cobalt hardly avoid some defects, such as longer extraction time, co-extraction and too many stages. In this paper, a microfluidic extraction procedure for simultaneously separating copper (Cu2+) and cobalt (Co2+) ions in a microchannel was investigated. In addition, some key operation parameters, such as initial pH, volume flow rate and extractant concentration, were optimized by a method of response surface methodology (RSM). The result showed that under the optimized operation parameters of initial pH of 2.5, volume flow rate of 0.035mLmin-1 and extractant concentration of 17.36%, the extraction rate of copper could be as high as 96.73%, with a low cobalt extraction rate, which was only 2.41%. [ABSTRACT FROM AUTHOR]