The invention discloses a high-strength valve for steam. The high-strength valve comprises a main valve body, and the upper end of the main valve body is provided with a valve flange used for controlling connection and disconnection of the main valve body; the portion, located under the valve flange, of the main valve body is provided with a first installing flange, the upper end face of the first installing flange is provided with a positioning boss in an upwards extending mode, a seal sleeve is arranged over the first installing flange, the lower end of the sealing sleeve is provided with a second installing flange matched with the first installing flange, and a seal ring is arranged between the first installing flange and the second installing flange; the positioning boss is slidably matched with an inner hole of the seal sleeve, the first installing flange and the second installing flange are both provided with corresponding connecting holes, and the first installing flange is provided with an installing groove used for installing the seal ring. According to the high-strength valve for the steam, the structure is simple, the cost is low, the safety and reliability are achieved, the service life is long, stopping is not needed for replacing, only a secondary seal structure needs to be utilized to seal the overall valve again, therefore, the production persistence and stability are facilitated, and the production efficiency is improved.