The utility model discloses a lead casing plate for a metal encapsulation casing. The lead casing plate comprises a kovar alloy layer, an oxygen-free copper layer and a ceramic layer from the interior to the exterior and in brazing connection. The utility model provides the novel lead casing plate for an airtightness encapsulation casing and adopting ceramics and kovar alloy, which takes the oxygen-free copper (TU1) as the transitional fitting material for the brazing of the ceramics and the kovar alloy. The utility model has the advantages of flexible option on brazing technology, simplicity and convenience in implementation, good product quality, and elegant appearance, effectively avoids quality problems of conventional brazing such as ceramics tearing and nickel and tin climbing, greatly improves the production efficiency of metal encapsulation casing, and effectively lowers the cost.