Wide band gap metal oxides as an important group of semiconductors have attracted great interests in recent years. They have important applications in electronics, optoelectronics, sensors, etc. In my talk, I will first briefly introduce our achievements on the controlled synthesis of 1-D nanostructures with different morphologies. Then, I will focus on our recent progress on transparent electronic devices built on metal oxide nanowires, which showed high mobility, high on/off ratio and high transparency.