Soil total nitrogen (STN) content is an important parameter to ensure the normal growth of crops and measure the nutrient abundance of soil, and it is also the most important indicator for variable fertilization decision of crops in base fertilizer period. In order to establish a set of rapid online measurement method for soil total nitrogen content, a vehiclemounted soil total nitrogen detection system software was developed based on Windows. The design of the detection system included architecture design and function design. The MySQL database management software was used as the database for development and design, and the data interaction between the detection system software and the MySQL database was realized; the software function design mainly included the main interface design of the detection system, the design of data acquisition and analysis interface, and the trajectory mapping interface design of the soil data detection points based on HTML5 geolocation technology. When the vehiclemounted soil total nitrogen detection system performed soil detection, soil spectral data at different sensitive wavelengths were collected by the software of detection system, and soil total nitrogen content was obtained by inversion of the soil total nitrogen content prediction model embedded in the software of detection system. Simultaneously, the acquired GPS information was used to generate the trajectory map of the soil data detection points through the HTML5 geolocation technology. Finally, the software of detection system was tested. The test results showed that the vehiclemounted soil total nitrogen rapid detection system software could effectively collect and display soil spectral information at different sensitive wavelengths, soil total nitrogen content and GPS information, and accurately generate the trajectory map of soil data detection points. It proved the reliability and stability of the software working of vehiclemounted soil total nitrogen rapid detection system based on Windows. It could meet the needs of field online rapid detection of soil total nitrogen content and generation of soil data detection points trajectory map.