The invention provides an urban spatial big data-based urban redevelopment and land recognition method and a system. The method comprises the steps of A, determining a preselected city region to be subjected to urban redevelopment and land recognition, subjecting the preselected city region to grid division so as to obtain a plurality of land units, and generating a candidate re-development land unit assembly formed by the plurality of land units; B, according to preset prohibitive identification indexes, selecting the candidate re-development land unit assembly to obtain feasible redevelopment land units, and generating a feasible redevelopment land unit assembly; C, according to preset introductory identification indexes, establishing a multi-target urban redevelopment land urgent degree evaluation model; D, according to the multi-target urban redevelopment land urgent degree evaluation model, evaluating feasible redevelopment land units in the feasible redevelopment land unit assembly to form urban redevelopment land units. According to the invention, the micro-scale objective identification for the land is provided.