Blood analysis plays a major role in medical and science applications and white blood cells (WBCs) are most often the target of analysis. We proposed an integrated microfluidic chip for rapid trapping WBCs from whole blood directly. The microfluidic chip consists of two basic functional units: a winding channel to mix and arrays of two-layer trapping structures to trap WBCs. Red blood cells (RBCs) were eliminated through moving the winding channel and then WBCs were trapped using the arrays of trapping structures. The microfluidic chip was fabricated in the biologically compatible PDMS (polydimethylsiloxane) using MEMS (microelectromechanical system) fabrication technology. We determined the critical flow velocities of tartrazine water and brilliant blue water mixing and whole blood and red blood cell lysis buffer mixing in the winding channel. They are 0.25 μl/min and 0.05 μl/min, respectively. The critical flow velocity of the whole blood and red blood cell lysis buffer is lower due to larger volume of the RBCs and higher kinematic viscosity of the whole blood. Under this flow velocity, the RBCs were lysed completely by mixing and the WBCs were trapped by the trapping structures.