Focusing on the asymmetric feature of uplink and downlink channel in traditional narrowband wireless communication such as short wave and ultrashort wave, this paper proposes a control method of reliable high performance data transmission for RTU in hydrology.It applies technologies including data relay with size reshape, data relay with interval reshape, auto data retransmission, sendoutthenwait and so on.According to actual network status, it can adjust the size of package, transmission time interval, and number of retransmission, as well as control the transmission rate.By using the proposed method, it is possible to control the key factors of successful data transmission of RTU under the situation of sudden message increase. Therefore, it can strengthen the control ability of RTU communication protocol, and provide solution to adapt IOT applications.