The invention belongs to the field of traffic control and specifically relates to an efficient energy-saving speed guiding method based on the green wave control of urban trunk intersections. After the light color display situation of downstream intersections and the time needed by the dispersion of queuing vehicles behind stopping lines are synthetically considered, and the speed of traffic flows on urban trunks is guided from two aspects: when the condition that the vehicle can pass the downstream intersection at the current speed is detected, a stable driving speed is recommended to a driver, and if the vehicle is driven at the speed, the vehicle can pass the intersection controlled by downstream signals, without stopping; and when the condition that the vehicle can not pass the downstream intersection at the current speed is detected, an deceleration advice is given, the stopping and waiting time of the vehicle at the downstream intersection can be decreased as much as possible, and therefore, oil consumption is reduced. By using the method, the dispersion of vehicle queues can be avoided, the green light utilization ratio of the downstream intersection is increased, meanwhile, the purpose of umimpeded driving of the traffic flows on the trunk can be really achieved, and emission is decreased; and the speed guiding method has the advantages of simple control operation, good real-time performance and the like, and can efficiently guide the traffic flows on the urban trunks and improve the benefit of the green wave control.