The design height of windshield wall is one of the key parameters for cold protection and keeping the warmth of offshore platforms in winter. This article proposes a design process and calculation model for the height of the windshield from the perspective of the closed space of the offshore platform, and checks the design height of the windshield from the perspective of adequate ventilation requirements in the enclosed space, and determines the critical height of the windshield wall on the offshore platform. Taking a platform in the Bohai Sea as the engineering background, the above model is used for case calculation and analysis. Based on the ventilation rate of the offshore platform being 12 times/h air change, the critical height of the platform deck windshield wall is determined as 4.5 m through numerical simulation and calculation of the ventilation rate. The above research results can provide a valuable reference for the calculation of the windshield wall height in the engineering design stage of the offshore platform.