With a preset echo sounding velocity, each bathymetric measurement can be corrected off-line numerically. This article presents an iteration algorithm of acoustic calibration for a representative acoustic profile versus depth of water column obtained in the survey area. In addition, different kinds of acoustic profile, represented by polynomial regression equations, were addressed offshore north Taiwan. Results gave a large variety of patterns in acoustic profile with in a small limit of territories in the shelf region, indicating that bathymetric measurements collected off northern Taiwan should be calibrated with much care. However, using an expected mean velocity at 1525 m/s, sounding accuracy with deviation less than 0.2% was obtained on the shelf in the summer.