The invention discloses a vehicle-mounted ATO energy-saving control method for an urban rail transit CBTC system. The vehicle-mounted ATO energy-saving control method for the urban rail transit CBTC system includes the steps of sorting the operation of the on-board ATO energy-saving into four phases and analyzing the condition of energy consumption in each phase, specifically, the four phases include: a accelerating phase, a cruising phase, a coasting phase and a braking phase; by adoption of genetic algorithm and combination with the analyzed results of the condition of energy consumption, transforming the solution to the minimum energy consumption to the solution to the best transfer points from the accelerating phase to the cruising phase, from the cruising phase to the coasting phase, and from the coasting phase to the braking phase; calculating by adoption of off-line methods, and obtaining the best transfer points of entering the cruising phase, the coasting phase and the braking phase. The vehicle-mounted ATO energy-saving control method for the urban rail transit CBTC system is beneficial for reducing energy consumption, and making the final operation time approximate to the planned total operation time to the maximum extent.