In present work, the relationships between electrical conductivity, hardness and microstructures of 7050 alloy during isothermal quenching in 180℃~250℃ following solid-solution treatment were investigated. Results show that in the initial stage of isothermal quenching at 180℃ and 200℃, electrical conductivity of isothermal specimens is lower than that of the specimen direct water quenching following solid-solution treatment and with the increase of isothermal time, hardness of isothermal specimens in natural aging temper increases at first and then decreases. With isothermal quenching at 180℃ for 128 min GPΙ zones and η’ phases are formed in matrix, with isothermal quenching at 200℃ for 32 min GPΙ and GPΙΙ zones are formed in matrix, and with isothermal quenching at 250℃ for 32 min η’ and S phases are formed in matrix. The formation of strengthening phases during isothermal quenching is the main reason for the hardness of specimens increase in natural aging temper. When 7050 alloy plates are isothermal quenching at 200℃ for 16 min following solid-solution treatment, their T6 temper hardness is only 3.4% lower than that of the direct water quenching plates and their conductivity increases by 9.2%, which are close to the properties of RRA treated plates with the regression regime of 180℃ for 32 min. Therefore, taking isothermal quenching at 200℃ for 16 min as a pre-treatment process following solid-solution treatment it will make 7050 alloy plates obtain excellent comprehensive properties.