The future mobile communication network will face the challenges of high mobile data traffic and more terminal data types, and the resulting effective technology with low latency and low energy consumption is required. Mobile edge computing (MEC) arises as an emergent technology for meeting the above requirements. MEC can run the computing offloading and resources storage on the edge of the network, which can greatly reduce the processing time delay and energy consumption, and contribute to a better quality of user experience. Firstly, the paper summarizes the fundamental principles and technical characteristics of MEC. Then, through specific MEC application scenarios, the paper further summarizes the advantages of MEC. Finally, on the basis of the existing work, the challenges and prospects of MEC are discussed. MEC will promote the integration of computing and communications, and power 5G towards new stage with the multiple technology fusion.