The fast regeneration switching rate of pyrolysis gas dryer will affect the system stability. In severe cases, accidents of unqualified ethylene products may occur. Through the analysis of the regeneration process of the cracked gas dryer in the 800,000 tons/year steam cracker at ZhongKe (Guangdong) Refinery & Petrochemical Company Limited, this paper analyzes the problems including the COT temperature runaway caused by fast cold regeneration rate, the system fluctuations caused by parallel switching and the user shunt timeout of the regeneration system, and proposes some effective methods such as presetting the fuel gas system during regeneration and determining the priority of generation users to mitigate the system fluctuations caused by the regeneration switching of pyrolysis gas dryer, thus ensuring the stable production of the unit.