This paper proposes a feedback model for virtual laboratory based on components. Because of the feature of virtual laboratory based on components, we transform the experimental procedure and device parameters into specific strings firstly. At the same time, the experimental reference library including standard experimental procedure strings has been established. Then, the experimental procedure strings of users actually are built and the standard experimental procedure strings of the experimental reference library including execute the pattern matching. According to the results based on the pattern matching, experimental guidance will be given to the users. This model meets the needs of learners for evaluation and guidance in correcting during virtual experiment, and also provides a solution idea for improving learner's experience.