With the advancement of underwater Internet of Things (IoT) technology, Underwater Wireless Sensor Networks (UWSN) have gradually become a forward-looking technology for marine resource exploration. Faced with the highly dynamic characteristics of UWSN links, it is important to design a reliable and energy-balanced routing scheme. To this end, this paper proposes an Opportunistic Routing protocol based on Link Quality (ORLQ) to address these issues. The Chan algorithm is used to establish distance relationships among nodes in UWSN, thereby obtaining the coordinates of ordinary nodes. Based on this, the Signal-to-Noise Ratio (SNR) of received data packets is a key factor affecting link quality. The Shannon theorem is used to evaluate the data packet throughput of the link and is used as an influencing factor for the next hop node, designing a link quality metric. Simulation results show that ORLQ outperforms existing routing protocols in terms of network throughput and energy efficiency.