The construction of high-speed railways is now in full swing, and the connectivity and integration of the underground space surrounding high-speed railway station has become one of the most important factors affecting the traffic efficiency. The current research mostly starts from qualitative analysis, lacking in systematic quantitative research on the interior of the space. Based on that, the research objects are mostly focused on the urban spatial analysis at the macro scale. Therefore, this study focuses on the connectivity and integration planning of the underground space of the high-speed railway station, the research scope of the underground space of the high-speed railway station is determined by referring to the existing research, space syntax is used as the main research method, and depthmap is used as the main spatial analysis tool to build a model, selects suitability indexes to measure connectivity performance, and two optimization schemes for comparative research are proposed through the modeling research of existing cases, which are further comparatively compared. The results show that: 1) The connectivity center exhibits a strong overall effect on improving the connectivity performance of underground space surrounding high-speed railway stations; 2) The main axis exhibits a strong local effect on improving the connectivity performance of underground space surrounding high-speed railway stations; 3) In the layout of underground space surrounding high-speed railway stations, it can be considered to combine the connecting axis with the connecting center to improve the connectivity performance. This paper could provide relevant suggestions for the connection and integration of underground space in the high-speed railway station area.