Compared to native speakers, Chinese learners show regular and systematic errors in using referring expressions. With a comprehensive consideration of cognitive, pragmatic and linguistic factors, this study measures the self-referent's accessibility in discourse and attempts to discover the effects of cognitive accessibility, referential intention, Chinese grammatical and textual factors on the use of referring expressions. First, native Chinese speakers' preference taken as the benchmark, 53 entries of self-reference errors at the subject position were selected from the annotated HSK Corpus. Next, based on clause-level segmentation, the accessibility of the referent I was measured with four parameters. Then fine-grained analyses were presented to address pronominal redundancy and deficiency among the learners respectively. We posit that the use of referring expressions is simultaneously constrained by cognitive, pragmatic and linguistic factors. Cognitively, the addresser selects a referring expression by measuring the referent's accessibility that varies in saliency, competition, distance and unity. Pragmatically, motivated by communicative intentions, s/he would deviate from the Principle of Accessibility and adopt a referring expression to code the referent of lower or higher accessibility than its normal form. Despite possible syntactic constraints in the final output, the choice displays higher flexibility as a result of the predicates' referentiality and topic chains' diversity in Chinese discourse. Since clauses are juxtaposed for clause-union and discourse cues are used with indexical function, the addresser is expected to be context-sensitive. Therefore, the selection of a referring expression correlates the process of transferring mental activity to linguistic expressions with the combination of cognition and communication, subjectivity and objectivity.  The results show that pronoun redundancy is caused by the learners' difficulty in producing topic chains in contexts of high accessibility, and their unawareness of the indexical function of discourse cues in contexts of relatively low accessibility. Whereas, pronoun deficiency is triggered by the learners' failure to deliver the increased referential intentionality in contexts of high accessibility, and their incapability of using episode markers to judge discourse continuity in contexts of relatively low accessibility. Our findings would contribute to Chinese teaching pedagogy and discourse studies. Firstly, the structures and patterns of topic chains should be further incorporated into the pedagogical grammar and systematically taught to Chinese learners. Secondly, learners should situate themselves in discourse contexts to gain contextual sensitivity and inference capability so as to harness discourse cues and episode markers. Thirdly, learners should be aware that referring expressions and sentence boundaries are largely determined by cognitive and pragmatic needs rather than subject-predicate structure.