Based on diffusion mechanism, a program-controlled cyclic particle extraction on an integrated PDMS microfluidic platform is presented. The platform comprises on-chip pneumatic peristaltic pumps and valves connected to a PCbased relay board, hence allowing programmable manipulations. The main concept is cycling a sample stream along with an extraction stream multiple times to enhance the particle separation. A sample solution containing 3-μm and 0.5μm particles was utilized to demonstrate the process. The average flow rate was 4.75 mm/s and the extraction channel length was 84.3 mm. The relatively accumulative concentration for the 0.5-μm particle was 7.52% at the 1st cycle and became 37.99% at the 10lh cycle. The result shows an expected improvement of particle concentration after the cyclic extraction. Higher efficiency can be achieved with more cycles.