Abstract: An auxiliary test paper detection device includes a reagent cap and a test paper cassette. The reagent cap contains a detection reagent, a sealing member is arranged at an opening of the reagent cap. The sealing member can be opened or removed under action of external force. Test paper is arranged in the test paper cassette, a sample absorption section of the test paper is exposed, an observation window is formed in the test paper cassette. A result display area of the test paper corresponds to the observation window. A connecting structure for connecting the test paper cassette and the reagent cap is provided, and when the test paper cassette and the reagent cap are connected through the connecting structure, a closed space is formed in an inner cavity of the reagent cap. The sample absorption section of the test paper extends into the inner cavity of the reagent cap.