Title: BIL: Bandit Inference Learning for Online Representational Similarity Test. Abstract: Similarity analysis is commonly used to determine the size of the discrepancy between two representations of a distribution pattern. In contrast to classical representational similarity analysis, which identifies disparate types of representations based on their shared similarity structures in distance matrices, this article proposes an online hypothesis testing procedure that will be able to determine whether a representation's difference from a constant is more significant than a predefined margin for streaming data. As a basic reinforcement learning model, two-armed bandits (TAB) are used to construct test statistics that update online. To achieve the most efficient testing results, an optimal strategy is developed for the TAB process. Asymptotic test statistics are discussed in theory, as are its corresponding explicit density functions, which are more accumulated than the normal distribution commonly applied in classical statistical analysis. Since the power of the proposed representative similarity test (RST) method is higher than that of the classical test, simulation studies support the validity of the proposed method.