A microfluidic chip for cell alignment is studied

which is driven by one impetus and has controllable focusing-flow shape.Models with different length proportion of sample channel and sheath channel

and different angle between these two channels are set up and focusing flow within these models is simulated under different negative pressure.SPSS software is used for the regression analysis and model optimization.In chip fabrication

printed circuit board（PCB） is used to fabricate master and polydimethylsiloxane（PDMS） is used as substrate material to make PDMS—PDMS

PDMS—glass and PCB—PDMS chips.Under the driving of single pump

the width of the focusing flow can be controlled and different size of particles and cells can flow in a single line.The researching result provides basis for the choice of appropriate length and angle of the sample flow channel and sheath channel according to different size of cells.This chip is also cheap and useful.