Resolution method of chiral fenoldpam

The invention discloses resolution of a D1 dopamine receptor agonist drug and in particular discloses a resolution method of fenoldopam. The resolution method of the D1 dopamine receptor agonist drug comprises the steps of protecting a phenolic hydroxyl group and an amino group in the structure of fenoldopam, then carrying out chemical resolution with a chiral acidic resolution agent to obtain a pure optical isomer, and finally removing a protecting group and salifying to obtain optically pure methanesulfonic acid fenoldopam.