A microdevice for separating plasma from human blood comprising a blood flow channel (2) connected to a corpuscles flow channel (5) and a plasma flow channel (8) through a curved construction channel (15). Blood flow channel has width 150 to 400 μm and length 1-20mm, constriction channel (15) has width 60 to 200 μm, length 0.157 to 3.15mm and curvature angle 90-270° with inner radius 50 μm to 1mm and outer radius 110 μm to 1.2 mm and corpuscles flow channel (5) has width 200 to 700 μm, length 0.5 to 5mm and bend angle 40-70°. Plasma channel is sinewave shaped and has width 20-150 μm and length 10-50mm. Channels have uniform depth 20-120 μm (FIG. 1).