This article uses the curve equation model to describe the initial value problem of differential equations in BIM project management. A new set of rolling curve-solving models is established for step-aligning in BIM project management. Based on the premise that the differential equation can be solved numerically, we appropriately simplify or set the required relational functions in the equation. Finally, we use mathematical software to numerically solve the differential equation and obtain the discrete function of the rolling curve. The research shows that the accuracy of the step flatness and the width of the stepped groove formed by the rolling curve of the solution in this paper is better than the original solution.