This study aimed to assess the impact of different fertilization on the nutrient status of farmland soil in the Lhasa River Valley. Based on the long-term fertilization experiment initiated in 2008 at the Lhasa Agro-ecosystemo- Research Station of the Chinese Academy of Sciences，the continued monitoring data from 2008 to 2022 were analyzed. The change of main fertility indicators in the topsoil layer(0-20 cm)under four distinct fertilization models:no fertilizer(CK)，organic fertilizer(MF)，chemical fertilizer(CF)，and a combination of organic and inorganic fertilizers(MC)were examined. The results showed that the average yield of rapeseed，winter wheat，and spring barley in MC treatment was significantly higher than that in CF treatment，and organic fertilizer had a significant improvement effect on the soil nutrients of farmland in the region. Compared to CF，during the experiment period，the soil organic matter in the treatments of MF and MC increased on average by 72.12% and 57.17%，respectively，in addition，total nitrogen increased by 72.32% and 41.04%，alkali-hydrolyzable nitrogen by 50.78% and 44.18%，and readily available potassium by 206.98% and 60.45%，respectively. Notably，the improvement effect became more significant with the extension of fertilizer application time. Between 2020 and 2022，the soil organic matter was increased by 115.75%-117.88% and 79.91%-87.42%，total nitrogen increased by 115.75%-117.88% and 69.19%-78.47%，while alkali-hydrolyzable nitrogen increased by 62.39%-130.77% and 98.82%-110.38%，respectively. From the perspective of annual changes，the soil organic matter，total nitrogen，alkali-hydrolyzable nitrogen，readily available potassium，and pH value all showed an upward trend with the application of organic fertilizer and combined organic and chemical fertilizer. In contrast，for the treatment of CF，soil organic matter，total nitrogen，and readily available potassium were decreasing，with significantly reduced readily available phosphorus and a trend of soil acidification. Correlation analysis showed that apart from soil pH，soil organic matter content had a significant positive correlation with other nutrient indicators. In particular，it was extremely positively correlated with total nitrogen，alkali-hydrolyzable nitrogen，and available potassium，and soil organic matter was the key to improve local soil nutrients. These results suggested that the continuous application of organic fertilizer had a significant conservation effect on the nutrients of Tibet Valley farmland soil，and its effect became more pronounced with increased application time. Therefore，in this region，we should continue to increase the input of organic fertilizer，reduce the use of chemical fertilizer，and provide a foundation for sustainable agricultural development in Tibet Plateau.