The invention provides a coordinated control system for a grade crossing of a tramcar. A control strategy that the single tramcar is relatively prior to other walking manners in the grade crossing is provided to solve the problems that a signal control system of the modern tramcar is complex, the passing efficiency of the grade crossing is low, the crossing includes much interference and a hidden safety hazard exists when the tramcar and social vehicles pass in a mixed way. A common four-phase grade crossing serves as a research object, and influence on the social vehicles is reduced as possible on the basis that prior passing of the tramcar is ensured. A strategy of green-light extension, red light early cutoff or phase crossing is selected for phase control, and in special conditions, a prior phase insertion strategy is adopted to improve the passing efficiency of the grade crossing. The system is conducive to high-efficiency, safe and convenient operation of the tramcar.