In order to meet the high accuracy calibration requirements for the power sensors with different joint forms in 9 kHz~50 GHz broadband, the calibration methods and principles which use thermistor to transfer quality values were analysed, and the necessity of using standard thermistor mounts with different joint forms to build the broadband calibration systerm was put forward. And in order to save the cost ,a high accuracy multiple power bridges was designed to solve the connection problems of standard devices with different joint forms in the system. Finally, the calibration experiment and data analysis of using the power standard devices with different joint forms to calibrate the power sensors with different joint forms respectively were carried out, the superiority of this broadband system was proved.