The present invention discloses a 5G mobile communication method and system based on MEC (Mobile Edge Computing) and a hierarchical SDN (software defined network). The method includes the following steps that: S1, a business request is received and is forwarded to an MEC edge node; S2, a Packet-in message is sent to an MEC node controller through the switch of the MEC edge node; S3, whether the MEC edge node has business consistent with business requested by the business request is judged; S4, a total controller performs network slicing planning and selection according to the business request, and then sends a Packet-out message to a core network controller included in an SDN sub-controller; S5, the core network controller performs resource scheduling processing on a mobile network, and buffers business or services related to the business request to the MEC edge node according to current resource occupation quantity; and S6, a terminal acquires the business or services from the MEC edge node. With the 5G mobile communication method and system provided by the technical schemes of the invention adopted, problems such as delay, congestion and capacity of a network can be solved, and ultimate experience of terminal users can be realized. The method and system have the advantages of high traffic, low time delay, low energy consumption, high reliability and the like.