Message acknowledgement mechanism in RabbitMQ includes confirm and ack. If the message doesnot need to be persisted, when the producer receives confirmation, the message may still be lost and the producer canot know that, so consumers may not receive the message. If the message needs to be persisted, when the producer receives confirmation, the message may be on the way to consumers. This study optimizes the message acknowledgement mechanism in RabbitMQ. After optimization, confirmation is sent to the producer after receiving the ack. The producer resends the message if the message is lost. Information that needs to be recorded is reduced during the message acknowledgement process. The producer receives confirmation after consumers receive the message successfully. The reliability of transient tiny messages delivery is improved. The experimental results reveal that the method can improve the sending rate of persistent tiny messages obviously when the number of clients is small.