[Objective] The temporal and spatial distribution characteristics of land ecological security along the main stream of the Yellow River were determined in Shaanxi Province in order to provide a scientific basis and technical support for maintaining the local land ecological environment, and to provide suggestions and a significant reference for other regions of the similar type. [Methods] A land ecological security evaluation system was constructed by DPSIR, and the time and space characteristics of land ecological security in the Shaanxi section along the main stream of the Yellow River from 2000 to 2020 were analyzed using the entropy method, the natural breakpoint method, and the improved TOPSIS method. An obstacle degree model was introduced to diagnose obstacle factors. [Results] ① The comprehensive value of land ecological security increased from 0.448 7 in 2000 to 0.535 3 in 2020, and the comprehensive security level increased from intermediate to good; ② From 2000 to 2020, the central and northern regions increased from intermediate to good comprehensive security, and the south region remained intermediate; ③ The individual results of the evaluation of land ecological security were different, and the trends showed different changes; ④ The driving force, state, and pressure relative to the obstacle index changed at average annual rates of 5.81%, 6.81%, and 5.51%, respectively, from 2000 to 2020; the impact and response decreased at average annual rates of 26.74% and 33.43%, respectively; ⑤ The main factor obstacles changed from the per capita net income of farmers and forest coverage in 2000 to total grain output, per capita construction land area, and per capita ecological land area in 2020. [Conclusion] Land ecological security in the Shaanxi section along the main stream of the Yellow River has reached a good level in time and space, but there is still a gap in order to achieve the high quality level. Therefore, in the future, it will be necessary to identify the pertinent area along the main stream of the Yellow River, adhere to classified guidance, adapt measures to local conditions, promote green development, reward and punish peers, and promote land ecological security to a higher level.