In recent years, horizontal wells have witnessed an increasingly extensive application, playing a pivotal role in the exploration and development of unconventional oil and gas reservoirs, such as shale gas, and offshore oil and gas reservoirs. Nevertheless, horizontal well logging still presents a plethora of challenges pertaining to factors affecting corrections, data processing, and interpretation. To explore the impact of tool eccentricity on acoustic logging in horizontal wells, relevant physical simulation experiments and numerical analyses were conducted. Energy parameters of mode waves were extracted under varying eccentricity conditions, and an in-depth analysis of the relationship between mode wave energy and tool eccentricity was carried out. The findings reveal that, when the tool is in an eccentric state, the energy of mode waves exhibits a relationship akin to a negative exponential function with tool eccentricity. Furthermore, we have observed an S-shaped curve relationship between tool eccentricity and the energy attenuation coefficient of mode waves. These research results serve to elucidate the influence pattern of tool eccentricity on the acoustic logging response of horizontal wells and provide valuable guidance for further investigations into correction strategies regarding the impact of tool eccentricity on array acoustic logging responses.