Abstract: Based on the decoupling theory, a decoupling model was constructed, the decoupling elastic coefficient of urbanization level and farmland security stress index were calculated in Santai county, and the decoupling state between them were divided. The research showed that the urbanization level of Santai county increased steadily from 2006 to 2018, and the farmland security stress index generally showed a fluctuating decline. The decoupling trend of urbanization level and farmland security stress index in Santai county mainly presented strong negative decoupling, strong decoupling, expansion negative decoupling, and weak negative decouplingfour types, which presented dynamic alternation. From the perspective of decoupling and coupling relationship, the change of decoupling state in the recent 13 years was generally manifested as the transformation from deformity to ideal state, although there was a relatively negative state in some years. The decoupling state presented stage characteristics: From 2007 to 2011, the decoupling state showed a trend of gradual improvement from the unideal state, and the coordination between urbanization level and farmland security showed unreasonable and gradual optimization and adjustment in the early stage. From 2012 to 2018, the overall performance of this phase showed that the decoupling state oscillates and was stable in a reasonable state and a relatively negative state, and the coupling relationship between urbanization level and farmland security was basically stable in a coordinated and relatively coordinated state.

Key words: north Sichuan region, urbanization, safety of cultivated land, decoupling