Hiya TianTianMa. London accommodation is (as you probably know - or if not are about to find out!) not really reasonably pried anywhere - more varying shades of pricey to very pricey! But wages are much better here than most places too, so it's swings and roundabouts.
Sorry to be blunt, but do you have any idea of figures? Are you renting or buying? What's your budget, and what do you expect for it (e.g. are you after a 2 bed?)
This will have a big bearing on which places you should be looking at, as prices vary widely.
Round where I live, for example, private rented 1 bed flats are about £200 a week. Go half a mile into the fashionable bit with good schools down the road, and you could be looking at £300 a week. Go half a mile in the other direction to the rough bit and you could get 1 bed place for £150. Regarding buying, for my area at least, you can simply add thousands on to the end - so a 1 bed flat here is about £200,000; £300,000 in the posh bit, and £150,000 in the crappy bit.
Prices here are inflated by it being pretty central, but then also kept down by being off the tube network.
Prices in the rest of London will be different.
So, if you give us an idea of budget, you'll get a much more realistic idea of where's doable.
HTH