Arctic sea ice is an important factor in the global climate and exerts a significant influence on acoustic propagation in the Arctic marine environment. Because obtaining measurements of the structure and acoustic velocity of sea ice is challenging, particularly on account of the field experimental conditions in the $85~^{\circ }\text{N}$ circle of the Arctic Ocean, the characteristics of the structure and acoustic velocity of sea ice in this region have rarely been reported. In this study, we used ground-penetrating radar (GPR) to detect the structure of the sea ice and a sound velocity meter to test the acoustic velocity of the ice core in the short-term ice station located at $85^{\circ } 28.863^{\prime }$ N, $179^{\circ } 48.807^{\prime }$ W during the 11th Chinese National Arctic Research Expedition. The ice core was located in the middle of the GPR lines. The structure and acoustic velocity of the sea ice model within the 85° circle of the Arctic Ocean were established on the basis of the data processing results. The model revealed the fine structural characteristics and vertical acoustic velocity distribution of the sea ice within the 85° circle of the Arctic Ocean in summer. This model may serve as an important reference for future research on the coupling of global sea ice and climate, as well as acoustic propagation characteristics, in the Arctic Ocean environment.