Abstract: Designing an early warning system for cultivated land ecological security can help us make advance analysis and warnings for the ecological security of cultivated land, which plays an important role in guiding the rational use of regional cultivated land resources and formulating scientific and reasonable agricultural development policies. From the perspective of the PSR model to construct an index system, this paper uses the entropy method and multi-factor comprehensive weighting method to evaluate the ecological security of cultivated land, and then proposes an integrated model of random forest and multi-layer neural network (RF-MLP integrated model) to predict the level of ecological security of cultivated land, and finally the early warning system for cultivated land ecological security was constructed. We used the main grain producing areas in China as an example to verify the system. The system runs smoothly, the accuracy is qualified, and the reliability is high. It has made a useful attempt to realize the commercial operation of cultivated land ecological security monitoring and early warning, and it has strong application value. The results show that: (1) The early warning system built with the RF-MLP integrated model as the key technology uses the random forest model to optimize the input attributes of the multi-layer neural network, which not only optimizes the selection of relevant features to improve the prediction accuracy of the model, but also avoids excessive features leading to over-simulation. It has made a useful attempt to realize the commercial operation of cultivated land ecological security monitoring and early warning. (2) The application results show that the ecological security value of cultivated land from 2006 to 2017 showed an overall upward trend, but the growth rate was not high. the warning level is changed from medium to light, and the spatial pattern of the warning situation shows the distribution pattern of the northern provinces with higher warning level than the southern provinces. From 2018 to 2027, the ecological security of cultivated land in major grain-producing areas has been improved, but the warning level remains at light warning. During the forecast period, the spatial pattern of the warning situation has basically stabilized. In some areas, such as the Northeast and the Huanghuaihai Region, the cultivated land ecology has great potential to develop in a positive direction. However, although the cultivated land ecological security in the middle and lower reaches of the Yangtze River is generally great, the security value has declined somewhat, and the warning level has changed from no warning to light warning.