A method for determining the quality of a microfluidic device, the method including placing a microfluidic device including a valve on a stage; radiating light on the valve of the microfluidic device; detecting light reflected from the valve using a photodetector; opening the valve of the microfluidic device; and comparing a change of the light reflected from the valve when the valve is opened with previously-stored reference data to evaluate a quality of the microfluidic device, wherein the valve of the microfluidic device includes a valve seat, which protrudes into a microfluidic path, and a polymer film, which opens and closes the valve.