The blowout during shallow oil‐gas exploitation always increases the failure risk of the offshore platforms and equipment on them. The thermo‐solid dynamic response of offshore structures in blowout accidents is significant for the process safety evaluation and post‐disaster recovery. A new safety evaluation method was proposed using blowout scenario modeling on the offshore platform and the structural safety evaluation of wellhead devices through the fluid‐thermal‐solid coupling analysis and reduced yield strength method. The results indicated that the blowout flame was significantly affected by the blowout gas velocity, and environmental wind strength, low blowout gas velocity, and high wind speed can lower the flame height and aggravate the safety conditions of the wellhead devices. The proposed method can be applied to the process safety evaluation of offshore structures in blowout accidents.