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With the development of urbanization, the security of the regional cultivated land system was facing certain threats, and the evaluation of the security of the cultivated land system was critical as an important measure to improve the security status of the regional cultivated land system and ensure the safety of food production. Taking the Changsha-Zhuzhou-Xiangtan (Chang-Zhu-Tan) region as the research area, from the perspective of systematic protection of cultivated land quantity, cultivated land quality and cultivated land ecology, to construct a safety evaluation index system of cultivated land system, and the improved projection pursuit model of quantum genetic algorithm was used to quantitatively analyze spatial and temporal evolution characteristics of cropland system security and identify its key factors. The results showed that the projection value of each subsystem in the study area presented a state of “staggered decrease”, and the comprehensive safety projection value of the cultivated land system presented a fluctuating decreasing trend of “first increase, then gentle and then decrease”, from 1.2521 in 2009 to 1.2517 in 2019. In 2019, the safety spatial pattern of the cultivated land system in the Chang-Zhu-Tan region showed a differential characteristic of radial improvement from the central urban area to the surrounding distant and suburbs. In view of different cultivated land system safety grade areas, regulatory measures were put forward according to local conditions. The total cultivated land area, per capita cultivated land area, cultivated land reclamation rate, mulch load per unit of cultivated land area and sewage treatment rate were the key factors affecting the safety of the cultivated land system in the region, and it was necessary to actively maintain and improve the safety status of the local cultivated land system in terms of protecting the amount of cultivated land and improving the level of utilization and management of cultivated land. The results can provide theoretical support for cultivated land protection and highquality social and economic development in Chang-Zhu-Tan region.