This study aims to understand how attitudinal factors influence individuals’ choices for further developing carsharing. To address the gap, a household survey was carried out to obtain the individual’s attitudes toward carsharing. The Transtheoretical Model is used to divide the adoption process of carsharing into five stages, including precontemplation, contemplation, preparation, action, and maintenance. Two Integrated Choice and Latent Variable Models with or without the attitudinal features are evaluated for the effects of latent attitudes on the above five stages. Additionally, the attitudinal factors at each stage are analyzed and compared, and the effects of the flexible and hard measures on the adoption process are discussed. The results indicate that the proposed attitudinal factors well reflect individuals’ adoption stage of carsharing and show different effects on the five adoption stages. The policy implications for facilitating carsharing require coordinating flexible and hard measures in different cognitive stages.