Ecosystem multifunctionality (EMF) refers to the ability of ecosystems providing multiple services and functions. Grazing is a primary method for developing and utilizing grassland resources. However, the impact of grazing disturbance on the EMF of grassland is not known well, and the factors driving the changes of impact are still unclear. In this study, we focused on the grassland ecosystem in the middle part of the northern slope of Tianshan Mountain. We conducted field plant community surveys, indoor determination of soil physics and chemistry, and microbial high-throughput sequencing. The objective of paper was to analyze the patterns of grassland EMF under different grazing treatments: light grazing, heavy grazing, and no grazing. The results showed that (1) compared with heavy grazing, ecosystem single functions such as grass productivity, soil carbon, nitrogen, phosphorus and potassium nutrients were significantly increased under light grazing, while EMF was also significantly increased (P<0.05). (2) The linear regression analysis revealed significantly positive correlation between single function and multifunctionality, as well as the plant Shannon-Wiener index, soil bacteria Shannon-Wiener index, soil fungi Shannon-Wiener index, and soil water content (P<0.05). Additionally, there was a significant negative correlation with soil bulk density (P<0.05). (3) Overall, structural equation model revealed that grazing had directly negative effect on EMF. However, grazing could also have indirectly negative effect on EMF through plant diversity and soil bacterial diversity and their interactions. The consideration of the response of multiple ecosystem single functions to grazing could provide more accurate picture of ecosystem change. This paper highlighted the significance of maintaining the stability of the function and multifunctionality of grassland ecosystems by plant community diversity and soil microbial community diversity. It also suggested that light grazing could be a viable strategy for conserving biodiversity and maintaining the stability of EMF in grasslands. The findings of this paper provide theoretical guidance for sustainable management and development for grassland ecosystems in the middle part of the northern slope of Tianshan Mountain.