The invention discloses an efficient data transmission method under a narrowband communication condition, and belongs to the field of wireless communication data transmission. The method comprises the following steps: issuing wireless channel resources and user information needed to participate in data transmission services by a base station; after receiving and parsing the information by a terminal, automatically calculating an allocated service channel and a launch window, automatically completing the migration to the service channel and performing window matching on time synchronization information issued by the base station broadcast in real time; and finishing data transmission on the corresponding launch window, and after the data transmission is finished, returning to a control channel by the terminal itself. The whole process of business execution does not need base station intervention, so that the frequent signaling interaction between the base station and the terminal is avoided, the consumption of air interface resources is reduced, and the air interface resources are sufficiently used for the transmission of valid data. Especially in the case of multi-terminal concurrent data transmission application scene, the speed and efficiency of data transmission are improved remarkably.