This study investigates the effects of linguistic difficulty and task type on the use of Chinese ba construction by second language learners. One hundred and ten adult learners completed four tasks orally (i.e., an oral production task prompted by video clips, an oral imitation task, a grammaticality judgement task and a correction task), as well as a background questionnaire and a one-on-one post-task interview. Twenty-two native speakers of Chinese served as baseline. Results demonstrate that the variable type of the Chinese ba construction which is subject to functional constraints is harder to learn than the obligatory type which is subject to obligatory syntactic constraints, and that the oral tasks were more challenging to perform than the metalinguistic tasks. The findings suggest that a series of factors including functional value and discourse context contribute to the linguistic difficulty of Chinese grammar features. The processing constraints of completing tasks and their interaction with linguistic characteristics explain the learning difficulty of the two types of the ba construction.