The present invention relates to a service system and method for supporting the preservation of the value of non-resident securities and, more specifically, to a service system and method for supporting the preservation of the value of non-resident securities, by which non-resident securities issued via a trust company are paid to the non-resident-securities-related account of an owner, the trust company dividing real estate, left in trust therewith by a user, into resident shares and non-resident shares for issuing the non-resident securities, and which provide a joint-pool service for providing support so as for goods or services of a seller to be purchased using the non-resident securities as standard money, thus can improve the liquidity of funds invested in the real estate, further support the control of the shares so as to preserve the value of the non-resident securities, and thereby provide a market using the non-resident securities.