Virtual assembly instruction refers to the assembly guidance instruction that superimposes virtual assembly guidance information on the real environment, making the product assembly guidance procedure more intuitive and convenient. Presently, virtual assembly instructions lack the capacity for adaptive adjustment; as a result, this research was conducted. First, the concept of intelligent assembly instruction with adaptive capability is proposed, and then the overall design framework for intelligent assembly instruction is constructed based on its definition. Then, the key components of intelligent assembly instructions, namely the dynamic decision-making of assembly guidance content and the intelligent selection of visual display mode, are designed. Finally, we construct a prototype system to demonstrate the adaptability of intelligent assembly instructions during the assembly guidance process. The experimental results demonstrate that the intelligent assembly instructions presented in this study are capable of providing dynamic assembly guidance for assembly tasks and can intelligently determine visual display mode. Intelligent assembly instructions decrease the difficulty of assembly, enhance the user’s comprehension of assembly guidance information, and provide a positive assembly experience.