Abstract: Sigma phase is a precipitate that can cause deterioration of the mechanical properties of 2205 duplex stainless steel, and its precipitation amount is determined by different aging treatment systems. This article investigates the effect of aging treatment at different temperatures and different periods on 2205 duplex stainless steel. The influence of sigma phase precipitation behavior and properties was analyzed. The relationship between sigma phase content, material elongation and hardness, and recommendations for coiling temperature and cooling method in actual production were made. Initially during the aging process, sigma phase precipitates at the δ/γ interface, followed by continuous growth to form a coral like bright white phase; The sigma precipitation pattern of the phase conforms to the trend of isothermal transformation curve (TTT curve). along with the increase in sigma phase precipitation which enhances the tensile strength and hardness of the material, but the elongation decreases and plasticity deteriorates. It is recommended to control the coiling temperature below 800 ℃ and cool it quickly in actual production.