The public blockchain, which is open to the whole network and has no user authorization mechanism, has received widespread attention from the industry. The Algorand mechanism with good scalability and low fork probability is widely used in the public blockchain. However, the Algorand mechanism has low consensus efficiency and does not satisfy the high frequency trading scenarios. In order to solve these problems, firstly, a Multi-Block Algorand (MB-Algorand) mechanism was proposed to improve the block consensus efficiency. Then, a Hybid-Algorand (H-Algorand) mechanism based on Algorand mechanism and MB-Algorand mechanism was proposed, which can ensure both the block consensus efficiency and security. The simulation results show that the H-Algorand mechanism can obtain a significant improvement in the consensus efficiency of blockchain network in expense of a small loss of security performance when the committee is under the Distributed Denial of Service (DDoS) attack. When the probability of a block consensus failure is 1%, the proposed mechanism makes the blockchain network consensus efficiency increased by 37.87% with only 4.9% loss in the security performance.