Abstract: The present invention provides a polypeptide capable of crossing the blood-brain barrier. In the present invention, C-terminal of the ziconotide is linked to N-terminal of a cell membrane penetrating peptide via one glycine to obtain a polypeptide capable of crossing the blood-brain barrier. The polypeptide of the present invention is suitable for intravenous, intraperitoneal or nasal administration with convenient operation and low clinical risk. It has a long pharmacological effect in vivo, excellent analgesic effect, and slight peptide side effect after intravenous, intraperitoneal or nasal administration, and is suitable for large-scale clinical applications. The polypeptide of the invention has the advantages of simple preparation, controllable preparation process and quality during the preparation, and is suitable for large-scale industrial production.