Based on the complex interrelationships among the three strategic basic resources of water, energy and food in important cultivated land reserve areas, a collaborative security evaluation study of water-energy-food was carried out in this paper. Focusing on saline-alkali land, an important cultivated land reserve resource in China, the PSR analysis method was adopted to establish a collaborative security evaluation index system for water-energy-food in typical saline-alkali region. The cloud model and variable fuzzy recognition model were comprehensively applied to construct a collaborative security evaluation model for water-energy-food in typical saline-alkali areas, and the model is applied in Dongying City, a typical saline-alkali area, as an example. The results show that the collaborative security level of water-energy-food in Dongying City shows a gradually rising trend. The relative shortage of water resources and their rational allocation in agricultural production and energy extraction are important factors affecting the collaborative security level of the three. Accordingly, countermeasures and suggestions for improving the collaborative security of water-energy-food in saline-alkali areas are put forward from two aspects: strengthening the rational allocation of water resources and carrying out saline-alkali land transformation in cultivated land reserve areas according to local conditions.