The invention relates to a novel chalcone compound Chalcone-1203, and also relates to a preparation method for the compound, a composition using the compound as an active component and application of the compound in preparation of an antidepressant drug. The novel chalcone compound Chalcone-1203 provided by the invention has substantial anti-depression effect. Results of animal testing in the embodiments show that Chalcone-1203 can substantially reduce immobility time of mice in forced swimming test and tail suspension test of the mice, has fast action and small toxic and side effect (TD50>2000 mg/kg), is suitable for long-term usage and shows valuable antidepressant pharmacological properties. The novel chalcone compound uses widely-available and cheap raw materials, is simple to prepare and can be used for preparation of antidepressant drugs of a variety of dosage forms.