We report a microfluidic immunoassay consisting of a precise and efficient mixing unit for transient multi-cytokine detections secreted by lymphocytes.This device has a detection micro-chamber with a Taylor dispersion-based mixing unit.We inject cytokine-sensitive fluorescence micro-beads for the quantitative detection, which can be activated by incubating the beads with the detection reagents (for providing fluorescent signals to quantify the bound cytokines on beads) and the bio-sample secreted by cells containing target cytokines. We perform experiments to verify the mixing scheme on its robustness and efficiency. We calibrate labeling fluorescence intensity profiles of 6 independent cytokine-sensitive beads,each conjugated with a specific antibody, using a confocal microscope for measuring the intensity. We demonstrate the high detection efficiency for concentrations of cytokine released by primary human T-cells. Further, we propose a high-throughput microfluidic immunoassay integrated with the 8 x 8 independently operated detection micro-chambers.achieving high-throughput detection functionality. Altogether, further development of this device can lead to profiling of multiple cytokine dynamics of lymphocytes for deeper understandings of the human immune system as well as the immune diseases.