The present invention belongs to the field of biochemistry and molecular biology. Provided is a mutant of α-conotoxin peptide TxID, a pharmaceutical composition and use thereof. The TxID mutant can specifically block acetylcholine receptors (nAChRs), in particular α3β4 or α6/α3β4 subtype, and has application prospects in the preparation of smoking and narcotic cessation and analgesic medicaments, medicaments related to the treatment of mental diseases and cancers, medicaments used for appetite regulation and neuroscience tool medicaments.