Abstract: A pocket scanning tunnelling microscope(STM) has beenbuilt on a KYKY-1000B scanning electron microscope(SEM). It consists of (1) a vibration-reduced system. (2) tunnelling tip. (3) tip scanning and approch system. (4) electric control and image acquisition system. The resolution of STM is about 1 nm. The semiconductor grating and gold film have been measured with this SEM+STM combined system.