The invention relates to a mutual access authentication method, which comprises the following steps: 1) a first entity sends an access authentication request group to a second entity, the second entity verifies whether the sign of the first entity is correct, if it is, calculates the shared primary key of the second entity; 2) the second entity generates an access response group and sends to the first entity, the first entity verifies whether the sign of the access response group is correct, if it is, calculates the shared primary key of the first entity; 3) the first entity sends an access authentication acknowledgement group to the second entity, the second entity verifies the integrity of the access authentication acknowledgement; if the verification succeeds, the shared primary keys of the first and second entities are consistent, completing the access authentication. The access authentication method of mutual authentication, provided in this invention, is based on the identity mechanism and can be used for the verification of identity validity with simple operation and wide application range.