<p>Taking a swimming pool steel roof with a beam string structure in Shandong Province, China as the engineering background, a method combining field tests and numerical simulations was adopted to analyze the effect of temperature on the beam string structure. By monitoring and analyzing the data of the actual project, the force and displacement deformation conditions of the beam string structure under the action of temperature were obtained. The numerical simulation results of the beam string structure under the action of temperature were obtained using Midas/Gen software. The effects of different linear expansion coefficients, prestressing, and vertical span ratios on the static performance of the beam string structures were analyzed and discussed. The results show that with increasing temperature, the vertical displacement and axial force of the top beam string increase, whereas the axial forces of the brace and tension cables decrease. With increasing temperature, when the linear expansion coefficient is less than 1.2 × 10^− 5/°C, the axial force of the tension cable and the brace increases. When the linear expansion coefficient is greater than 1.2 × 10^− 5/°C, the axial force of the tension cable and the brace decrease. With increasing prestressing, the absolute values of the axial force and the bending moment of the top beam string increase. With increasing vertical span ratio, the deflection and axial force of the tension cable decrease, and the absolute value of the axial force of the top beam string also decreases. The research methods and conclusions of the present study can provide valuable references for thermal design, monitoring and control of beam string structures.</p>