Covert communication has been using to prevent confidential information from being leaked to an unintended receiver. In this paper, we present a general purpose novel methodology for blockchain-based covert communication system design to be used in Bitcoin environment. Blockchain is a distributed system which combines P2P network, consensus protocol, encryption algorithm to complete the first reliable cryptocurrency system Bitcoin. According to the high security and convenient access of this technology, many applications based on Blockchain such as smart contracts, distributed cloud storage have been developed. However, in the field of covert communication, there are few researches are applied in Blockchain. Therefore in this paper, we propose a system called Covert Communication based on Bitcoin Regtest Self-built Network (CCBRSN), which takes Blockchain as a covert communication channel and embeds encrypted messages into Blockchain’s addresses to transmit. In this model, users can transmit covert messages via Blockchain mutually and fast. Finally, we provide experimental analysis for our proposal to show that it is suitable for practical application.