Abstract: Direct sequence code division multiple access (DS/CDMA) as a technique for underwater acoustic networks is attracting attention from researchers Adaptive chip-level equalization based on channel estimation is proposed in this paper Time variability of the underwater channel requires that receiver adaptation be performed at the chip rate,rather than the symbol rate Channel estimation is used to cancel inter chip interferences caused by hypothetically transmitted chips prior to linear equalization By selecting only significant channel components,computational complexity is reduced Simulation is carried out to evaluate the equalization performance.