Current BIM software for structure design is just a simple copy of the original design process. And it doesn't improve the working efficiency. In the age of BIM, the main value of disciplines' cooperation is how to obtain other disciplines'data automatically and efficiently. Through the research on Structural Auto-Calculate-Load-System based on BIM, the author puts forward the following viewpoints: it can improve cooperation efficiency greatly by setting data pre-process module at data exchanging in different disciplines. Furthermore, the pre-process module can reduce the dimension of data exchanging automatically and make auto-identification possible. In summary, it improves the level of BIM application in structure design.