plasmid extraction - (Feb/17/2012 )

What is your question? It could be plasmids, but what size are you expecting? what are the sizes on your ladders (I think you have two on there)?

i expect there will be smooth, clear and nice band appear..but it looks like a bad result, right? i use 1kb DNA and 100bp DNA as ladder

Plasmids typically have multiple bands - corresponding to the different forms you find plasmids in, supercoiled, nicked, and linear. You may see all of these or only a subset depending on howgood you are at preparing the DNA.

How big are you expecting your plasmids to be?