Vocabulary plays a crucial role in foreign language learning, and vocabulary mastery proves to be challenging at different competence levels. Compared to other areas of research into Chinese as a foreign language, vocabulary acquisition and vocabulary teaching have rarely been investigated. The aim of this study is to investigate the relationship between vocabulary learning strategies and vocabulary size and to verify whether vocabulary size is positively correlated to proficiency level. A total of 95 Italian undergraduate Chinese learners, from elementary to intermediate levels, participated in this study. The participants were first given a vocabulary learning questionnaire and then a vocabulary size test. Statistical and qualitative analyses of the data revealed two trends: a poor variety of vocabulary learning strategies and a positive correlation between vocabulary size and proficiency level.