This paper carries out an environmental law big data analysis using big data computing based on the legislative framework of biodiversity in Inner Mongolia grassland. For the research and analysis of the rule of law guarantee for the ecological security of the Inner Mongolian grassland, it first establishes the early warning of the ecological security of the Inner Mongolian grassland through the gray prediction model and verifies the accuracy and feasibility of the prediction model precision. According to the early warning results of the ecological security of the Inner Mongolian grassland, it is suggested to enhance the legalization of grassland ecological compensation. The R2 GM (1, 1) prediction model of Inner Mongolia grassland reaches 0.86, which shows that the prediction accuracy is good. The ecological security evaluation of Inner Mongolia from 2025 to 2035 presents, in terms of type, a safer state region > safer state region > mildly alerted state region > moderately alerted state region > seriously alerted state, and the percentage of each grade increases or decreases. Without distinguishing occupations, 93.3%-98.6% of all herders and grassland managers supported that grassland ecological compensation should be legalized. This shows that the construction of the rule of law guarantee for grassland ecological security in Inner Mongolia is an inevitable trend of development.