Introduction  In order to obtain detailed seafloor topographical information， an application of multi-beam sounding system in offshore wind farm survey is proposed.

  Method  Taking an offshore floating wind power equipment development project as an example， the principle and composition of the Reson SeaBat T50-P multi-beam sounding system were introduced in detail， through the implementation of the project， the results were analyzed and the accuracy was evaluated.

  Result  Through the practical application of this project， it is verified that the multi-beam sounding system has better convenience， high efficiency and reliability in the offshore wind farm survey.

  Conclusion  The practice of this project provides a good reference for other similar offshore wind farm surveys.