As the target of shale gas exploration and research, N1 natural gas in Mangya Sag, Qaidam Basin is still in the initial stage, and the understanding of shale gas enrichment conditions is relatively vague. According to the research ideas of shale gas, the reservoir-forming factors of N1 in Mangya depression, such as structural evolution, sedimentary environment and source rock conditions, are re-sorted, and the following understandings are formed: (1) N1 in Mangya Depression was one of the sedimentary centers of the western Qaidam basin. In the later period, local uplift formed the current pattern of two depressions and one uplift. In the middle, there was the Nwest-southeast Katemirik-Youdunzi anticlinal belt, both of which were depressions in the south and north; (2) N1 in Manya Depression is a saline lake basin with deep water, strong reducability, closed stability, and water environment for the formation of laminaceous lime-cloud shale and lime-cloud shale. In the middle and lower sections, middle-high abundance and high maturity source rocks are developed, and gas production is large; (3) N1 shale is developed with micro-nano intergranular pores, high free gas content and brittleness index; (4) N1 in Mangya sag is a "source-reservoir integrated" reservoir formation combination with high gas content and brittleness index, and has the characteristics of large longitudinal span, multiple sweet spots and high-pressure shale gas reservoirs. Based on this understanding, the criteria for favorable shale gas zones are established: buried depth of 4100–6000m, TOC >0.6%, Ro >1.2%, carbonate content ≥40%, effective porosity ≥4%, gas content ≥2m3/t, and gas saturation ≥40%.