Abstract:   The rapid development of China’s offshore fishing, alone with rising fuel prices, there has been fishing boats’ energy and environment issues. When tuna longline is working, the diesel engine is in the low speed and low load operation conditions which cause higher fuel consumption. In order to stabilize the economic benefits of offshore capture fisheries and reduce energy and consumption, hybrid tuna longline system based on Beidou satellites is presented in this paper. This system consists of two power sources: the diesel engine and the electric motor. According to Beidou satellites, the system could choose different power sources based on position and speed. Compared with conventional hybrid tuna longline, the general fuel consumption can reduce 13％ under the same condition and the same working time. And also the system reliability and propulsion efficiency are improved.