Starting control method and system of transmission, and vehicle

The invention provides a starting control method and system of a transmission, and a vehicle. The starting control method of the transmission includes the steps that when a starting process of the transmission enters into a rotate speed control stage, a transmission shaft speed and an engine rotate speed are compared; if a difference valve between the transmission shaft speed and the engine rotatespeed reaches to an index valve, a required change gradient of the engine rotate speed is obtained according to a change gradient curve of the transmission shaft speed, the transmission speed shaft and the engine rotate speed; and according to the required change gradient of the engine rotate speed, the engine rotate speed is controlled, and thus smooth synchronization are conducted on the enginerotate speed and the transmission shaft speed. According to the starting control method and system, the problem that impact, abnormal sound and the like in the starting process affect driving feelings is solved, the entire st