The invention generally relates to the technical field of 
network communication, and particularly relates to a method for routing an 
underwater sensor network. The method for routing comprises the following constituent parts: (1) node grade definition; (2) node grade information acquiring and updating processes; (3) neighbor node information recording; (4) directional flooding 
mechanism based on grade difference; (5) 
adaptive routing step based on the grade difference, node density and 
residual energy; and (6) differential geographical routing step based on the grade difference and distance. The method has the following advantages that the best next hop 
adaptive routing is determined on the basis of the neighbor 
table information to reduce redundant paths, so that the energy efficiency is improved to a great extent; and the 
adaptive routing adopts immediate routing, so that the inhibition time of the conventional 
underwater UWSN (
underwater wireless sensor network) routing to a received 
package is avoided, and the time 
delay from terminal to terminal is reduced. A great deal of 
simulation experiments prove that through an underwater sensor network adaptive 
routing protocol based on the difference, the 
energy consumption can be reduced to a great extent, the time 
delay from terminal to terminal is reduced, the node utilization equity is improved, and the whole network 
life time is prolonged.