The use of DNA as programmable building blocks to achieve highly-definable nanostructures, termed as DNA nanotechnology, has offered great opportunities to control matter at a very small scale. Fast growing researches along this direction has led to the emergence of several significant branches of DNA nanotechnology. This review intends to summarize the recent developments in this area. Several topics will be discussed with a focus on the works from the authors' group, including (1) DNA self-assembly and DNA-directed self-assembly, (2) DNA nanomachines, (3) DNA-based electronics, (4) DNA assisted nanofabrications, and (5) DNA computations.