Existence value as a non-use value means that people feel lost when something disappeared. Exploring the existence value of grassland is a powerful tool for strengthening our awareness of environmental protection and for developing strategies for resource use. Contingent valuation method (CVM), a survey-based method, can reveal consumer preferences for public goods and services and infer respondents' willingness to pay (WTP) to improve environmental quality. After several decades of development, it has emerged as the principal means for measuring the existence value. Although it is questioned by its validity and reliability in decision-making processes, it has become a dominant technique for the valuation of non-market environmental costs and benefits since the 1990s. WTP technique of CVM was used to explore systematically the existence value of Maqu grassland, which is located on the eastern of Qinghai-Tibetan Plateau. The results showed that the average WTP of each household was 339 Yuan/a, and the total WTP was 0.03×10⁸ Yuan/a in 2005. WTP was positively related to the income. From 2005 to 2016, the income of local resident increased by about 20%, with the average WTP being 407 Yuan/a in 2016 and the total WTP being 0.033×10⁸ Yuan/a. Compared with other studies, the existence value of Maqu grassland was smaller due to the limited population base. However, if we considered the role of Maqu grassland in maintaining the global biodiversity and its importance for water conservation of the Yellow River, this existence value would increase largely, which reached up to 636×10⁸ Yuan/a in 2005 and to 763×10⁸ Yuan/a in 2016. From 2005 to 2016, the existence value of Maqu grassland increased about 20% which is equalled to an increase of the income. These results suggest that the existence value of Maqu grassland is significant, and we should consider it in cost-benefit analysis. Furthermore, the existence value changes with time and is needed to evaluate continuously in order to make the right decisions.