The method and device for judging blood agglutination, pre-place blood cells or serum of known blood type in the sample wells of the micropore plate, and place the blood cells or serum of the tested blood in each sample hole to form a reaction sample; scan the reaction sample in the sample hole Obtain the absorbance value of the absorbing point, define the effective absorbing point range centered on the middle absorbing point, and eliminate the absorbing points with errors on the edge; within the effective absorbing point range, select the minimum absorbance value and maximum absorbance value; use the minimum absorbance value as the base , obtain the difference between the maximum absorbance value and the minimum absorbance value, calculate the ratio of the difference to the minimum absorbance value as the base; preset the agglutination reference value, compare the ratio with the agglutination reference value, and when the ratio is greater than the agglutination reference value, set The blood in the sample hole is judged as agglutination, and when the ratio is less than or equal to the agglutination reference value, the blood in the sample hole is judged as non-agglutination. Quickly judge whether there is agglutination in the mixed sample, with high accuracy and wide application range.