In ethylene plant, dry flare gas needs to be superheated before it joins with wet flare gas. Several commonly used superheating methods are introduced in this paper, including natural heating, jacket heating and superheating via superheater. The design principles, technical characteristics and operation characteristics of these methods are discussed, and their advantages and disadvantages in preventing freeze blockage and reducing the consumption of low temperature materials are compared and analyzed. It is concluded that direct superheating via superheater has high safety and reliability and the lowest investment.