The utility model provides a micro-fluidic biochip which comprises a base chip, and a treating fluid pool, a connecting passage, an off-screening and collecting pool and at least two analyzing devices which are arranged on the base chip, wherein each analyzing device comprises sample pools, sample passages, a treating fluid passage, a public passage, off-screening passages, a screening passage and a screening and collecting pool; the sample pools are communicated with the sample passages; the screening and collecting pool is communicated with the screening passage; the sample passages and the treating fluid passage are simultaneously communicated with one end of the public passage; the off-screening passages and the screening passage are simultaneously communicated with the other end of the public passage; the treating fluid pool is communicated with each treating fluid passage through the connecting passage; and the off-screening passages are communicated with the off-screening and collecting pool. After different flow velocities of different sample passages or treating fluid passages are set, semen and treating fluid respectively flow towards the public passages at respective flow velocities via the sample passages and the treating fluid passages, so that sperms in different velocity sections can be respectively captured and screened by utilizing a laminar flow principle.