Abstract Assembly accuracy is a critical factor in ensuring the performance of opto-mechanical components, directly impacting the assembly efficiency and practical application range. This article aims to enhance the pointing accuracy of opto-mechanical components by establishing the multi-fidelity model (MFM) based on the elastic interaction theory of multiple bolts and proposing a method for predicting and optimizing the assembly accuracy of opto-mechanical components considering the uncertainty of bolt preload. First, a physical equation representing the relationship between the bolt preload and the normal deviation of optical elements is established based on a multi-bolt interaction stiffness matrix. Second, an efficient MFM is constructed by combining a small sample of simulation data with the physical equation. Third, the uncertainty distribution of bolt preload is quantified to predict the assembly accuracy, and a predictive model for the assembly accuracy of opto-mechanical components is developed. Finally, through geometric parameter optimization design, the propagation of uncertainty in preload impact on the assembly accuracy is effectively controlled, and the prediction accuracy and optimization effect of the model are experimentally validated. The results demonstrate that the optimized assembly accuracy of opto-mechanical components improved from 32.3 arc sec to 4.8 arc sec, representing an 85.1% relative improvement. Additionally, the predicted value of the optimized structure is 4.5 arc sec, with a prediction error of 6.3%. This article provides theoretical guidance for the efficient and highly accurate prediction and optimization design of the assembly accuracy in opto-mechanical components.