With the rapid development of industry in China, the number of establishments that are proposed or under construction is increasing year by year, and many are industries that handle flammable, explosive, toxic, harmful, and dangerous substances. Accidents such as fire, explosion, and toxic diffusion inevitably happen. Accidents resulting from these major hazards in cities cause a large number of casualties and property losses. It is increasingly important to analyze the risk of major hazards in cities realistically and to suitably plan and utilize the surrounding land based on the risk analysis results, thereby reducing the hazards. A theoretical system for risk assessment of major hazards in cities is proposed in this article, and the major hazard risk for the entire city is analyzed quantitatively. Risks of various major accidents are considered together, superposition effect is analyzed, individual risk contours of the entire city are drawn out, and the level of risk in the city is assessed using “as low as reasonably practicable” guidelines. After the entire city's individual risk distribution is obtained, risk zones are divided according to corresponding individual risk value of HSE, and land-use planning suggestions are proposed. Finally, a city in China is used as an example to illustrate the risk assessment process of the city's major hazard and its application in urban land-use planning. The proposed method has a certain theoretical and practical significance in establishing and improving risk analysis of major hazard and urban land-use planning. On the one hand, major urban public risk is avoided; further, the land is utilized in the best possible way in order to obtain the maximum benefit from its use.