The encoded microparticles,especially fluorescence-coded microparticles,can serve as important carriers for multiplex molecular analysis1.However it is difficult for the optical decoding techniques to eliminate the spectra overlap or interference of the fluorescence signals of multiple fluorescence materials.We developed a novel encoding way to increase the code number requiring no complicated decoding process.It combined color,intensity and position code by preparing quantum dot(QD)encoded microparticles in a microfluidic system.Flow lithography 2 was used to generate the QD encoded hydrogel microparticles.Multiphase laminar flows of hydrogel monomer(poly(ethylene glycol)diacrylate,PEGDA)mixed with a photoinitiator and QDs were introduced in a microfluidic chip,under which a simple shutter device was positioned to control an intermittent exposure of PEGDA.The photopolymerization of PEGDA caused the encapsulation of different QDs in distinct zones of the hydrogel microparticle,which provided the possibility of position code.If the number of color,intensity and position of the QDs stream were respectively named as m,n and I,the code number can be calculated as c=(mn)i/2-mn/2(i≥2).The present method shows several advantages.First,the code number is increased.For example,when all of the color,intensity and position code were 3,the code number of the previous method 3 and of the present one are 26 and 360,respectively.Second,the decoding process is simplified.Fluorescence signals from the same microparticle are more distinguishable because the QDs are compartmentalized in different zones.So it could use decoding equipments without high performances in sensitivity and resolution.Third,the size of microparticles is controllable.QDs-encapsulated microparticles with uniform size could be produced with the flow rate in a range of 0.1-0.3 μL/min and the exposure time in a range of 10-75 ms.