Summary: LTNC-HP, a novel optimized recoding algorithm for the protection of high-degree packets in underwater acoustic sensor networks, is proposed. The proposed algorithm improves the performance of a data transmission scheme and is based on the combination of LT codes with network coding. Moreover, the algorithm decreases the variation in the degree distribution of LT coding packets after passing the network coding at the relay point. By introducing a high-degree protection transmission algorithm at each intermediate node, the proposed algorithm can resolve the imperfect coverage of the input symbols and decrease the amount of data transmission. Moreover, the priority selection mechanism for the same degree packet is added in LTNC-HP when coding at each relay node, significantly improving the efficiency of coding information at each relay node and increasing the diversity of the data packets in the network. Simulation results showed that compared with existing encoding algorithms, LTNC-HP improves the effectiveness of the information transmission and decreases transmission redundancy.