The invention discloses a voltage coordination control method based on step weight optimization. According to the method, in an optimizing scene after large-scale system disturbance and fault, through a key control object and measurement of identifying, restoring or stabilizing voltage, an optimizing scale can be controlled to a relatively fixed range, thereby remarkably reducing optimization calculation amount and effectively preventing a problem of decision set explosion. Furthermore, information required for step weight optimization is a process amount of model predicative control calculation, and no additional calculation time is required fundamentally. Based on a track sensitivity method, a complicated nonlinear programming problem is converted to a mixed integer programming problem which can be relatively easier handled, thereby greatly reducing optimization complexity.