This paper is the result of ecological geological survey engineering. Objective Under the background of global climate change and the continuous expansion of human activities, natural ecosystems and their service functions are facing increasingly serious threats and recessions.In order to address this challenge, it is critical to identify and protect key sites that are of great value to ecological sustainability. Ecological security pattern refers to a comprehensive strategy and method to ensure regional ecological sustainability. Methods Based on the In–VEST model, PLUS model and circuit theory, this study evaluated the dynamic changes of ecosystem services and ecological security pattern (ESP) in the Tianshan Mountains in the arid region of Northwest China. Results The spatial distribution of land use type (LUCC) was basically stable from 1990 to 2050. In the past 30 years, the total conversion area was 32.52×10³ km², which was mainly the conversion between wasteland and grassland. Compared with 2020, the total land conversion areas under the scenarios of Natural development scenario (ND), Ecological protection scenario (EP) and Urban development scenario (UD) in 2050 are 21.43×10³ km², 23.09×10³ km² and 22.87×10³ km², respectively. Among them, the net increase of forest land area is the most, which is mainly transformed from grassland. The area of forest land, grassland and water body increased under EP scenario. In the other two scenarios, the area of construction land and cultivated land has expanded significantly. Compared with ND and UD scenarios, the ecosystem service function of EP scenario is greater. There are obvious spatial differences in ESP in the Tianshan Mountains from 1990 to 2050. The larger ecological sources and smaller resistance corridors are mainly distributed in the central and northern parts of the Tianshan Mountains with higher ecosystem service functions. On the contrary, broken ecological sources and large resistance corridors are mostly distributed in the western region blocked by sand, bare land or mountains. The southeast is a desert area, with no ecological source and lack of ecological corridors. In the past 30 years, the area of ecological source area has decreased by 1.84×10³ km², showing a trend of fragmentation, and the ecological network is more complex. Compared with 2020, the area of ecological source and pinch point under EP scenario in 2050 will increase by 10.53×10³ km² and 0.11×10³ km² respectively, and the area of ecological barrier zone will decrease by 0.38×10³ km². In addition to the EP scenario, the ecological source area of the other two scenarios also increased, but lower than the EP scenario. Conclusions Ecological protection scenarios play a vital role in shaping LUCC and are of great significance for maintaining ecological security and ecosystem integrity.