Data transmission method and system, terminal and readable storage medium

The embodiment of the invention provides a data transmission method and system, a terminal and a readable storage medium, and the data transmission method comprises the steps: receiving a GRE message processing indication message comprising a GREKEY and an IP address at a 3GPP2eHRPD network element side from an SMF through a UPF, and transmitting an indication response message comprising a GREKEY at a PGW side and an S2a PMIP address to the SMF. The invention also provides a data transmission system, a terminal and a readable storage medium. The 3GPP2eHRPD network can be accessed to a 3GPP 5G core network; media do not need to be mutually converted between the GRE package and the GTP package, mutual conversion between the GRE package and the GTP package can be directly achieved through the UPF, and the characteristic advantage of gateway CU separation deployment is reserved; the media format conversion delay is reduced, the processing consumption is reduced, and the user experience is improved. 本发明实施例提供了一种数据传