[Objective] The spatial and temporal evolution of ecological security in Guanzhong plain urban agglomeration was studied in order to provide scientific reference for the formulation of ecological security measures in this area.[Methods] The social economy-natural ecology lotka-volterra symbiosis model and the DPSIR indicator system of ecological security were constructed to measure the ecological security status of Guanzhong plain urban agglomeration from 2008 to 2017. And the causes of ecological security problems were analyzed based on the measurement results.[Results] ① From 2008 to 2017, the social and economic development of Guanzhong plain was rapid, but the improvement of ecological environment was not obvious. ② From 2009 to 2016, the force direction of social and economic subsystems was positive, while that of the natural ecological subsystem was negative in many years, which indicated that the profit-oriented development model with rapid social and economic development and the damage of ecological environment existed for a long time in Guanzhong plain urban agglomeration.[Conclusion] Factors such as the slow pace of industrial structure optimization, industrial pollution, pressure on ecological carrying capacity caused by population expansion, and the occupation of rapid urbanization on natural resources have become important reasons that hinder the improvement of ecological security in Guanzhong plain urban agglomeration.