Method and system for transmitting data packet, terminal device and network device

A method and system for transmitting a data packet, a terminal device and a network device which are applied to the technical field of communications. The method for transmitting a data packet comprises: a terminal device acquiring a condition of using a small data packet transmission mechanism, and if the condition is met, the terminal device transmitting a data packet in accordance with the small data packet transmission mechanism, wherein the condition comprises any one or more of the following: the data volume of the data packet is less than a first threshold; the transmission of the data packet is within a preconfigured time; within a sliding time window, the total data volume of the data packet having been transmitted by the terminal device using the small data packet transmission mechanism does not exceed a second threshold; the application type of the data packet is a preconfigured application type; the terminal device is a preconfigured access type; and the data packet conforms to preconfigured attribute information. The transmission of a data packet is realized.