Abstract: Recently a series of studies that made by Oaksford suggested that Probability information has a strong influence on cognitive process of conditional inference so that it can be used to explain and predict peoples’ reaction in inference. So this article reviewed probability effects that conclude probability of antecedent and consequent, conditional probability, conjunctive probability，causal probability and added antecedent in conditional inference and recommended some recently studies and viewpoints, at last made a summary and expectation.

Key words: conditional inference, conditional probability, conjunctive probability, probability effect