The present disclosure relates to a kind of sodium alginate microsphere vascular embolus that contains water-soluble drug and preparation and application thereof. The embolus preparation falls into dry microsphere type and wet one that are made of degradable materials. The drug carrier can be sodium alginate, human serum albumin, chitosan or sodium hyalurate, solidifying and forming microsphere together with calcium ion solution under presence of static charge. The microsphere can have a diameter in the range of 20-1000 μm and can be divided into a wide variety of sizes in case of need. The present disclosure adopts raw materials that are good at mechanical strength, bio-compatibility, bio-degradability and stability. In vitro experiments, animal trials and clinical observations reveal that this embolus is a good targeting medication for embolism treatment and immunochemotherapy, which is safe, effective for the treatment of solid tumors including primary liver cancer, lung cancer, renal tumors, bladder cancer, uterine cancer, ovary cancer, colon carcinoma and rectal cancer.