A microfluidics device to detect microtubule-binding proteins was proposed using microtubule-kinesin based system. To provide "proof of principle", attachment of microtubule associated tau protein was detected via the change in kinesin velocity. The proposed device is capable of multiplex parallel assay of several experimental samples by using the same kinesin-coated beads moving in the same channel with immobilized microtubules. The results showed that the device successfully detected the hindered kinesin motion due to tau attachment on microtubule (MT) surface.