As a core competence in 21st century, computational thinking (CT) is of great significance for undergraduates. However, there are few researches on the CT evaluation about undergraduates, and nor do a theoretical framework. Additionally, it is not clear what factors may affect their CT development. Therefore, according to Marzano's new taxonomy of educational objectives, this study constructed a theoretical framework for the CT evaluation, which included the field of the CT knowledge and the CT system. Then a Computational thinking scale (CTS) among 737 undergraduates was verified. CTS was adopted to evaluate undergraduates' CT skills, and the factors that may affect their CT skills are discussed according to the framework. The results showed that: (1) the CTS had sufficient reliability and validity among the sample undergraduates; (2) the CT skills of the sample undergraduates were in the middle and upper level (M = 15.71, SD = 2.18); (3) personal factors (gender and major) and contextual factors (educational environment and school support) are related to undergraduates' CT skills. Several suggestions and countermeasures were put forward for the undergraduates' CT cultivation on the framework, which will provide a reference for CT in undergraduate education.