The invention discloses a reagent device for detecting an antinuclear antibody and a method thereof; the reagent device is long strip-shaped, comprises a substrate with eight hole sites and a handle disposed at one end of the substrate; the eight hole sites comprise a sample hole, an adjuvant hole, an enzyme conjugate hole, a substrate hole, a stopping solution hole, a diluent hole, a reaction hole, and a dilution hole, which are arranged in sequence from the end near the handle. The reagent device of the invention realizes antinuclear antibody detection with the device based on a principle of enzyme-linked immunoassay, is an independent, single-sample analytic detection method, and can be used cooperatively with corresponding specific analytical instruments; during detection, a detection reagent or a sample is injected by using a full automatic precision liquid filling device, which provides advantages of operation automation, accurate filling amount, high accuracy and precision of detection results; and the reagent device has wide application prospects.