Provided are a sodium salt of a uric acid transporter inhibitor and a crystalline form thereof, In particular, provided are a uric acid transporter (URAT1) inhibitor 1-((6-bromo-quinoline-4-yl)thio)cyclobutyl sodium formate (the compound of formula (I)), a crystal form I, and preparation method thereof. The obtained crystal form I of the compound of formula (I) has a good crystal form stability and chemical stability, and the crystallization solvent used has a low toxicity and low residue, and can be better used in clinical treatment.