The 87 cases of disputed paternity were analyzed.Among 87 cases,73(83.9~(96))were civil,14(16.1%)criminal.By testing of 12 blood group systems,25 alleged fathers were exclused while 76 alleged fathers were not exclused,in which RCP value were from 9.91% to 99.998% calculafed according to theEssen-M(?)ller theory.In this report the causes of the disputes blood groupsexcluded and the calculation of PI and RCP were discussed.