What's the best way to improve my speaking in English when i see a foreign film?

First of all, I would totally agree with your tactic of gaining fluency in a foreign language by watching films.

I don’t know what your native tongue is, or if you can speak other languages, but having the option of the subtitles in a language you know is best. I put on subtitles the first time I watch a film, and then the next time I watch it I will understand the whole story, and watch it without the subtitles. This way, you will understand the story, and be able to use the words they have used in the story to describe it better in english.

However, this way really only works when you are watching a dvd at home, or if you go to see the same movie a couple of times in a theatre. But, I would recommend buying a movie, and watching it lots of times, to get the accent right.

Look up words if you don’t know what they mean (dictionary), watch movies on DVD (so you can rewind the film if you didn’t understand or hear something right the first time), use English subtitles (like @lamedb said), but most of all: Do it alot, practice makes perfect (stick around on Fluther and have fun while learning).

Also, make sure you use punctuation in your writing: ‘when i see a film,i…’ —> ‘When I see a film, I…’ (I’m not making fun of you, but in order to speak fluently you need to think about what you’re writing and use that when you’re speaking. You don’t learn from just listening or reading English, you learn from trying to understand what they’re saying and how you can use those words in a conversation of your own later on).

I would recommend that you watch not only English movies with Chinese sub-titles, but also Chinese movies with English sub-titles, if you can find them there. Both will help, in different ways. Keep in mind that sub-titles are often very approximate translations of the actual dialog, and some are much better translated than others. Inevitably, a lot gets left out.

Talk to people who speak fluent English. Just talk. It’s good for ya. Anyways, my sister went to Italy for a year and she can now speak Italian fluently just because she interacted and spoke to people who spoke Italian. That’s what I would do anyway.

I’ve heard there’s software that can slow down audio files/podcasts and audio tracks of video files. Somebody in Germany who has the same issue mentioned this to me. Try Google.