Abstract: As an important metacognitive judgment, judgment of learning is the prediction about the future performance of learned materials. The underconfidence-with-practice effect ,which describes an underconfidence phenomenon that people underestimate their recall performance during a test on their repeated study., is an intriguing and counter-intuitive phenomenon in the field of judgment of learning. So far, most of the experimental evidence supports that the underconfidence-with-practice effect in the judgment of learning is robust and pervasive, whereas some other evidence demonstrated some constraints on the occurrence of the effect. With respect to the functional mechanism of this underconfidence effect, the researchers have proposed different theoretical models (such as the anchoring-and-adjustment hypothesis, mnemonic debiasing account, and the Memory for Past Test heuristic ) to investigate this effect in depth.. Finally, the limitations of the previous studies and the remaining questions to be resolved in the future studies in this field would be indicated in this paper