The invention relates to a 5-bromo-7-azaindolin-2-one compound represented by a formula (I) shown in the description, a preparation method therefor, medicinal use of the compound and an antitumor pharmaceutical composition adopting the compound as an effective ingredient. More specifically, the invention relates to a 4-oximido-1-piperidyl fragment containing 5-(5-bromo-2-oxo-1,2-dihydro-3H pyrrol[2,3-b]pyridin-3-methylene)-2,4-dimethyl-1H-pyrrol-3-formamide compound which has more superior anti-tumor activity compared with similar antitumor drugs, such as sunitinib.