Nowadays research on single CNT based nanoelectronic device arises much interest among researchers, but in the fabrication of CNT based nanoeletronic device, one of the key technical problems is to realize precise assembly and electrical contact between CNT and microelectrode. For solving the problem, first AC dieletrophoresis (DEP) method is used to coarsely position batch of CNTs near the microelectrode, then AFM based robotic nanomanipulation method is used to precisely position, assembly and make electric contact of the selected CNT. MWCNT assembly and electric contact experiments verify the effectiveness of these two methods' integration.