A sodium alginate crosslinked slow-released moxifloxacin microsphere, the preparation method of the microsphere, a vascular target embolus containing the microsphere and the use of the microsphere in preparing the vascular target embolus. The microsphere contains moxifloxacin, a drug carrier, a adsorbent, a reinforcing agent and a solidifying agent, wherein the drug carrier is sodium alginate, the adsorbent is albumin prepared from human plasma or bovine serum albumin, the reinforcing agent is gelatin or hyaluronic acid, and the solidifying agent is a divalent metal cation chosen from calcium salt or barium salt.