As a kind of cognitive radio network based on cooperative communication technology, cognitive cooperative network not only solves the problem of uneven distribution of spectrum resources in different networks in specific time and space, but also improves network performance through cooperation between primary and secondary users. However, with the increasing variety of wireless technologies and mobile applications, due to the inherent characteristics of wireless channels can lead to the loss of and fluctuation in performance of service quality, due to safety problems. To deal with the descending transmission of the cognitive cooperative network attacked by malicious users, we put forward a Blockchain-based safe transmission strategy. First, Blockchain is used for authentication, avoiding the loss of and fluctuation in transmission performance caused by data corruption. Second, Reed-Solomon (RS) codes are adopted for better error correction, further enhancing the stability. Eventually, the simulation result shows that the proposed strategy is more stable than existing transmission modes of the cognitive cooperative network.