The beam string structure，a new self-balancing system is a combination of a string (Cable), pole and beam-column (beam, arch). Because the beam string structure make full use of tensile properties of high-strength cord, force became more reasonable, transportation became more convenient and construction became more simple for the new self-balancing system. The beam string structure became a new structure with a good value and prospects. In this paper the effects of the static performance of the single truss string structure are researched through analyzing the influence of prestressed cable, pole pitch, blow-span ratio of cable and cross-sectional area of cable using of finite element theory. The results of the reasonable selection of string truss design parameters a valuable reference.