A method for user authentication based on feature information, comprising: judging whether a user to be authenticated belongs to a similar user group, wherein the similar user group comprises at least two similar users, and the similar users are users whose reference feature information meets a preset similarity condition and a preset distinguishability condition; and authenticating the user to be authenticated according to reference feature information in the similar user group if the user to be authenticated belongs to the similar user group; wherein the method further comprises: acquiring reference feature information and sample feature information corresponding to each one of at least two sample users, wherein the reference feature information of the at least two sample users meets the preset similarity condition; calculating, for any of the sample users, similarity degrees between the sample feature information corresponding to the sample user and the reference feature information corresponding to each sample user; judging whether the at least two sample users meet the preset distinguishability condition according to the calculated similarity degrees; and adding the at least two sample users to the same similar user group when the at least two sample users meet the preset distinguishability condition. judging whether a user to be authenticated belongs to a similar user group, wherein the similar user group comprises at least two similar users, and the similar users are users whose reference feature information meets a preset similarity condition and a preset distinguishability condition; and authenticating the user to be authenticated according to reference feature information in the similar user group if the user to be authenticated belongs to the similar user group; wherein the method further comprises: acquiring reference feature information and sample feature information corresponding to each one of at least two sample users, wherein the reference feature information of the at least two sample users meets the preset similarity condition; calculating, for any of the sample users, similarity degrees between the sample feature information corresponding to the sample user and the reference feature information corresponding to each sample user; judging whether the at least two sample users meet the preset distinguishability condition according to the calculated similarity degrees; and adding the at least two sample users to the same similar user group when the at least two sample users meet the preset distinguishability condition. acquiring reference feature information and sample feature information corresponding to each one of at least two sample users, wherein the reference feature information of the at least two sample users meets the preset similarity condition; calculating, for any of the sample users, similarity degrees between the sample feature information corresponding to the sample user and the reference feature information corresponding to each sample user; judging whether the at least two sample users meet the preset distinguishability condition according to the calculated similarity degrees; and adding the at least two sample users to the same similar user group when the at least two sample users meet the preset distinguishability condition.