We investigated a selective assembly method of fabricating single-walled carbon nanotubes (SWCNTs) on a silicon-dioxide (SiO2) surface by using only a photolithographic process; then, we fabricated 8 x 8 field-emission transistor (FET) arrays for sensor applications. Photoresist (PR) patterns were made on a SiO2-grown Si substrate by using the photolithographic process. This PR-patterned substrate was dipped into a SWCNT solution dispersed in dichlorobenzene (DCB). The PR patterns were removed by using acetone. As a result, selectively-assembled SWCNT channels in 8 x 8 FET arrays could be fabricated between source and drain electrodes without complicated chemical steps using octadecyltrichlorosilane (OTS). Finally, we successfully fabricated 8 x 8 SWCNT-based multi-channel FET arrays by using our novel self-assembly method.