As the most recent development of zkRollup Layer 2 technology，zkEVM has become one of the most important research area of blockchains. Aims at providing the DApp developers with an easy to use and general purpose zkRollup solution，this technology has a vision of fully compatible with EVM，just to embrace the well developed ecosystems of EVM. zkEVM is the typical application of state of the art cryptography technologies in blockchains and its ideas can be referenced in other areas such as privacy computations. This article will provide a bird eye view to its fundamental principles.