In the big data environment, the real-time processing requirement of data stream is high, and data calculations require persistence and high reliability. Distributed Data Stream Processing System (DDSPS) can solve the problem of data stream processing in big data environment. Besides, it has the advantages of scalability and fault-tolerance of distributed system, and also has high real-time processing capability. Four subsystems and their key technologies of the DDSPS based on big data were introduced in detail. The different technical schemes of each subsystem were discussed and compared. At the same time, an example of data stream processing system structure to detect Distributed Denial of Service (DDoS) attacks was introduced, which can provide the technical reference for data stream processing theory research and application technology development under big data environment.