The Internet has greatly enhanced the efficiency of information dissemination. Human society has fully stepped into the self-media age after two decades of rapid development. The blockchain, which is hailed as the internet of value, has dramatically increased the efficient distribution of digital assets and made self-financing possible. A broad range of industries will be remodelled by the blockchain in the future, just as the Internet has reshaped the traditional industries. There are usually two ways to achieve a historical breakthrough, one is through finance and the other is through technology. The combination of finance and technology is called Fintech and the core of Fintech is the blockchain. Blockchain was born with financial properties. Blockchain without financial properties can only be called a DLT distributed ledger. Other Fintech technologies, such as big data, cloud computing, artificial intelligence, can be applied to support finance. Nevertheless, finance is not the native property of these technologies. Blockchain technology began with Nakamoto’s Bitcoin, a peer-to-peer cryptocurrency system . Ethereum  expanded Bitcoin’s capabilities and intended to provide a blockchain with a built-in fully-fledged Turing-complete programming language for writing smart contacts, thus opening up a new blueprint for the restructuring of a variety of industries. Ethereum runs a smart contract based on the Solidity language that serves as a platform for writing and deploying DApp (distributed applications/blockchain applications). Finance is the exchange of funds and assets. In the new economic blueprint formed by the blockchain, it manifests as digital currency represented by bitcoin and digital asset represented by smart contract. Digital currency and blockchain record payment transactions in a distributed accounting system. Smart contracts allow users to customise rules and write code to express their logic. Both utilise the features of decentralisation and immutability of the blockchain to ensure the recording and delivery of value. Blockchain systems for smart contracts are faced with the following major problems at the same time: 1) There is a lack of a unified and effective Oracle. In the closed bitcoin ecosystem, all the data in the system is generated by the system, so there is no problem of the validity and authenticity of the data/knowledge itself. In a smart contract environment, however, there is a need to obtain the external system data/knowledge, and the validity and authenticity of external data/knowledge often becomes the bottleneck and obstacle of smart contracts. 2) Insufficient support for large-scale transactions. Inevitably, single-strand competition causes the waste of resources and browsing and restoring transactions are more complicated. 3) Increasing demand for cross-chain support. Handling the compatibility problems for smart contract data is far from easy. The PCHAIN Network is a new infrastructure level public chain system with native support for multi-chain applications and EVM, providing an open, scalable platform for third party developers in the industry and making it possible for large-scale enterprise applications based on smart contracts.