Underground space development in the old city is conducive to improving urban space quality and solving spatial contradictions. Underground space is an important means to improve the old city’s living environment and re-excite the city’s vitality. The ground and underground information integration system is the digital foundation and technical guarantee for the integration and intensive construction of the aboveground and underground space in the old city. Based on the data collection and research content of urban underground space information systems within the country and abroad, this paper extracts the limiting and influencing factors of space information systems, introduces big data integrated processing technology, and combines machine algorithms and related evaluation methods. The study proposed developing the aboveground and underground integrated development decision-making and data support platform suitable for the development and management of the underground space of the old city, aiming to provide data support and decision-making reference for the intensive development and digital management of the old city space, in addition, to promote the renewal of the old city and the urban style protection development.