The present invention relates to a real estate trust-based service system and method for supporting the preservation of the value of housing securities, whereby : housing securities issued via a trust company are paid to a securities account of an owner, the trust company dividing real estate, left in trust thereto by a user, into resident shares, and non-resident shares for issuing the housing securities; a joint pool service is provided for providing support so that goods or services of a seller may be purchased using the housing securities as standard money; and support is provided for controlling the shares in order to preserve the value of the housing securities, and thus a market using the housing securities is provided.