A method for designing all coverage of valid primer pairs, which satisfy various filtering constraints provided by users with respect to a given sequence database and has validated specificity to given sequences, is provided. By screening all suitable primer pairs present on a given DNA sequence database without omitting any one primer pair and also screening all primers having a coverage of 1 or more as well as primers having a coverage of 1, a user can be allowed to give rankings to the primers in order to easily select the primers having a high success rate in biological experiments from the resulting primers.
