The invention discloses an ABO, RhD blood typing reagent card, a preparation method thereof and an antibody diluting solution adopted in the preparation method. In the preparation method, the pH value of a system is maintained by virtue of a sodium phosphate buffer system, tween 80 is added, the component of a gel preservation solution is removed, and proper lubrication capability can be obtained when erythrocyte passes through the gap of gel, so that unaggregated erythrocytes have the capability of passing through gaps of gel particles, and aggregated erythrocytes cannot pass; nonspecific adsorption of the gel is eliminated by adding bovine serum albumin to protect the titer of the antibody; microbial contamination is reduced by adopting sodium azide, the preservation period of the product is prolonged, and blood typing error caused by microbial contamination is eliminated; and the gel is screened in the preparation process, and the gel raw material which is obtained by virtue of screening is required to be swelled, wet heat sterilization and cleaning, so that microbes contained in the gel are eliminated, the components of the gel preservation solution and broken gel particles are eliminated, and the product quality is greatly improved.