Systemic Functional linguistics considers Modality as the speaker’s attitude betwe en “yes” and “no”. Based on this, we discuss the Chinese modality system. First, we review what has been done on Chinese modals by the previous researchers. Then, we introduce Halliday’s modality system in English to establish a Chinese modality system and analyze the syntactic and semantic features of the typical modal verbs to point out the negotiation of Chinese modality.