The barrel vault structures are built by using enough aches side by side along with the distance. This type of structure has been preferred to construct from past to present. In the last century, the barrel vault structure frequently used to cover large span areas by using steel structural elements. The aim of this study is to present the optimization of steel double barrel vault structures without violating the some structural constraints such as nodal displacement, stresses and the buckling of the compression line element according to the AISC-ASD. For this purpose, a 384-bar double-layer barrel vault structure was selected as an example. The three dimensional (3D) finite element model (FEM) of the double-layer barrel vault structure was created with SAP2000. Analysis of the 3D FEM was conducted under the vertical concentrated loads which is are applied to the non-supporting joints of top barrel vault. In the optimization process a new proposed algorithm named Rao 1 is preferred. The MATLAB programming is used the data transfer from the SAP2000 for sending design variables and getting the stresses and nodal displacement of the structure. The efficiency of the optimization process was shown by comparisons with the available results in the literature.