Based on BIM technology and green building simulation software, this paper constructs a green building evaluation index system that evaluates buildings and improves and elevates spatial analysis. First of all, according to the relevant regulations in China, the index system combining BIM technology and green building simulation software is determined from the following aspects: safety, durability, health, comfort, convenience, resource saving and livable environment. And then the weight of each index is referred to its score value in relevant standards and the score of experts. Finally, the final green building score was obtained by combining the index score and weighted by layers. The final green building score was divided into four grades from low to high: Unqualified, Level 1, Level 2, and Level 3. From all the efforts above, the paper manages the overall evaluation of green buildings and provides information support for the subsequent green building optimization and transformation. To conclude, the green building evaluation index system based on BIM technology and green building simulation software can evaluate green buildings quickly and effectively. What's more, the green building can improve the space and make the green building effect more remarkable.