The present invention relates to a service system for supporting the value maintenance of housing securities based on a real estate trust, and a method thereof. According to the present invention, housing securities issued through a trust company which divides a real estate given in trust by a user into a residential stake and a non-residence stake for issuing the housing securities are paid to a security account of an owner. Also, a common pool service which supports to purchase goods or service of a seller by using corresponding housing securities as standard money is provided, and stake adjustment for maintaining a value of the housing securities is supported to provide a market using the housing securities. Accordingly, the user is supported to use residual securities except for a residential stake among the total stakes of a house to issue the housing securities while occupying the house through the residential stake of the house by giving the house in trust to a trust company. In addition, the housing securities deposited into an account of the user is provided to be used for purchasing goods or service of a seller, thereby securing liquidity for funds invested to a real estate, and also, supporting the user to stably reside in the house with limited capital. Furthermore, a value of the housing securities is maintained by adjusting the residential stake in a state of maintaining the residual stakes securing the housing securities when a value of the house decreases, thereby increasing stability and reliability for the housing securities as standard money.(20) Trust company(30) Joint pool service(40) Service operation company(AA) Periodic share(BB) Trust(C1, C2, C3) Housing stock(DD) SellerCOPYRIGHT KIPO 2019