Assessing shy symptoms via computerized adaptive testing (CAT) provides greater measurement precision coupled with a lower test burden compared to conventional tests. The computerized adaptive test for shyness (CAT-Shyness) was developed based on a large sample of 1400 participants from China. Item bank development included the investigation of unidimensionality, local independence, and exploration of differential item functioning (DIF). CAT simulations based on the real data were carried out to investigate the reliability, validity, and predicted utility (sensitivity and specificity) of the CAT-Shyness. The CAT-Shyness item bank was successfully built and proved to have excellent psychometric properties: high content validity, unidimensionality, local independence, and no DIF. The CAT simulations needed 14 items to achieve a high measurement precision with a reliability of .9. Moreover, the results revealed that the proposed CAT-Shyness had acceptable and reasonable marginal reliability, criterion-related validity, and sensitivity and specificity. It not only had acceptable psychometric properties, but also had a shorter but efficient assessment of shyness, which can save significant test time and reduce the test burden for individuals with less information loss.