Compared to other methods of growing single-walled carbon nanotube (SWNT), chemical vapor deposition (CVD) can produce purer SWNT at lower temperature, which also has the particular advantage of energy conservation. Moreover, with the CVD method, we can directly eposit single-walled carbon nanotube (SWNT) thin films on a substrate without further purification and transfer. By doing so, we can make those procedures easier. We deposit CVD-SWNT networks with different tube lengths on n+ silicon substrate by adjusting the growing conditions. The SWNT networks are placed on substrates as a thin film of CNT thin film transistors (CNT-TFTs) with a range of channel lengths and different electrode shapes (parallel or interdigitated electrodes). Then, electrical measurement was performed. It is found that electrical properties of CNT-TFT can be optimized by increasing SWNT tube length, but they do not have a simple linear relationship. Likewise, the use of interdigitated electrodes can increase urrent and has an effect on the on/off ratio by shortening the channel length and extending the channel width. In this thesis, we have successfully fabricated a CNT-TFT with higher efficiency by adjusting CNT length and TFT electrode shape.