Abstract: To solve this problem that the nodes send or receive a message is interrupted when enter a sleep state which reduces the data delivery success rate in existing sleep algorithms based on the periodic wake mechanism for opportunistic networks, a more Reliable sleep Scheduling algorithm base on Adaptive Time Adjustment (RSATA) is proposed. Combining RSSI ranging mechanism and message cross-layer notification mechanism, RSATA analyzes the contact process between the nodes to exclude the encounter chance node can not send data and then dynamically adjusts the wake time and sleep time. So RSATA algorithm avoids message sending and receiving interrupted by sleep. Simulation results show that, compared with AWS algorithm and ETAWS algorithm, RSATA algorithm not only improves the message delivery rate, but also reduces the number of messages sent, sending interrupt rate and nodes' energy consumption.