Ophiocordyceps sinensis is one of rare fungal species parasitizing the larvae of a moth of the genus Thitarodes (Hepialus), which mainly lives in the Tibetan Plateau of China (including Tibet, Qinghai, West-Sichuan, Southwest-Gansu, and Northwest Yunnan province) and the Himalayas (including India, Nepal, and Bhutan). Qinghai province is one of main yield areas of Ophiocordyceps sinensis resources in China by the statistics. Ophiocordyceps sinensis lives the most common occurrence of at an altitude of over 3000 m. Ophiocordyceps sinensis is commonly known as "yarsa gumba", also with a Tibetan name of "winter yarsa and summer gumba". Because of a highly valuable tonic in Traditional Chinese Medicine, the price of Ophiocordyceps sinensis has increased continuously from 21 RMB/kg in 1970 to 210 RMB/g in 2011. Ophiocordyceps sinensis has become the most important income source of local farmers and herders. Ophiocordyceps sinensis bring huge economic benefits to local farmers, herders and government. Among the stakeholders, there is a puzzled debate on conservation and sustainable commercial harvest on Ophiocordyceps sinensisis, so it is urgent to do scientific exploration and research on its biological characteristics, conditions in natural habitats, spatial distribution, product yield, and artificial cultivation to harvest timely. At present, the researches interested in Ophiocordyceps sinensis pay more attention on its medicinal function, physiology of its host insect and artificial cultivation etc. However, reports on quantitative characters and spatial patterns of Ophiocordyceps sinensis resources suitability are quite few but necessary. Herein, spatial distribution of Ophiocordyceps sinensis suitability in Sanjiangyuan region was studied based on spatial analysis of GIS. In this study, appropriate indices of eco-environment for Ophiocordyceps sinensis suitability,including landform factor, vegetation type, and soil type, were chosen according to habitat conditions. The field sampling data and questionnaires from herders were collected to verify the cartographic results. There were 18 sample plots and 54 quadrats from Zaduo county in Yushu Tibetan Autonomous Prefecture, Maqin county in Guoluo Tibetan Autonomous Prefecture, and Zeku county in Huangnan Tibetan Autonomous Prefecture of Qinghai province. 3 sample plots were selected in each county. The each sample plots comprised 3 random quadrats of 1 m×1 m. Thereinto, 9 excavation plots had more concentrated distribution of Ophiocordyceps sinensis resources and more excavation of farmers and herders, and another 9 control plots had no excavation of Ophiocordyceps sinensis. The distance was less than 4 km between excavation plots and control plots of Ophiocordyceps sinensis resources. Additionally, a total of 373 questionnaires of farmers and herders were designed in this paper. The results showed that Ophiocordyceps sinensis resources in Sanjiangyuan region were mainly distributed in central and south-eastern regions, with an area of 18.45×10⁴ km², accounting for 50.74% of the total area. Suitability areas accounting for more than half of the respective total area in Dari county, Gande county, Yushu county, Chengduo county, Maqin county, and Banma county, which are major producing areas of Ophiocordyceps sinensis resources. Suitability areas of GIS analysis were corresponded with field-measured data, which indicated that GIS-based suitability distribution for Ophiocordyceps sinensis resources was feasible. The study may provide scientific basis for comprehensive investigation, protection, rational development and utilization of Ophiocordyceps sinensis resources. Based on the aforementioned, government should further strengthen the management and protection of Ophiocordyceps sinensis resources in order to bring about the win-win benefits of the ecological and environmental protection and improving farmers and herders income.