Objectives  To enrich the study series of acoustic propagation characteristics of the proving field in limited water area, the characteristics of influence by sedimentary layer appearance and temperature-dominated sound velocity change on transmission loss at testing near field and far field are analyzed.

  Methods  Through Matlab and VB combined programming software, the corresponding acoustic transmission loss curves of different indentation shapes, sizes, numbers and distributions, and different sediment slope types and angles, different temperature-dominated sound velocity changes were obtained.

  Results  The results show that the influence of sedimentary layer appearance is slight, but it nonetheless eliminates the influence of unknown indentation features on the acoustic experiments of large-scale complex ship architecture and ocean structures; the influence of temperature-dominated sound velocity change on the near field is much less than the far field, and transmission loss at the far field generally increases with the increase in sound velocity,

  Conclusions  which offers a reference for acoustic experiments of the proving field in limited water area.