In The study, the bonding of WC-9%Co to SUJ2 steel using Ag-Cu-Zn-Cd insert metal has performed to investigate the bonding properties by heat-treatment. Bonding was brazed for 5-30min at 95$0^{circ}C$, performed solution treatment for 5 min at 85$0^{circ}C$ and sustained subsequently oil quenching. To investigate the effect of heat-treatment, tempering was executed at $600^{circ}C$ for 30 min after oil quenching. Mechnical properties and chemical compositions on the brazed bonding interface were investigated by means of microstructural observation, 4-point bending test and EDS and XRD measurements. The results obtained were as follows. 1) The bonding strength of WC-9%Co/SUJ2 joints by Ag-Cu-Zn-Cd insert metal obtained about 78, 117 and 72MPa after brazing for 5, 20 and 30 min at 95$0^{circ}C$. And the highest bonding strength obtained about 131MPa after brazing for10 min at 95$0^{circ}C$ 2) Higher bonding strength of 288MPa was obtained in the joint that brazed for 10 min at 95$0^{circ}C$, and carried out tempering for 30 min at $600^{circ}C$ subsequently. 3) Fracture of joint brazed by Ag-Cu-Zn-Cd insert metal for 5, 10, 20 and 30 min created WC-9%Co/SUJ2 interface. The joint that brazed for 10 min at 95$0^{circ}C$ and then tempered for 30 min at $600^{circ}C$ was fractured at the site of WC-9%Co.