which subway lines have been used from capital international hotel to beijing international convention

You must refer to BJ International Convention Center. Well then, no direct metro line can take you there. You should take Airport Express train to Dongzhimen. Then transfer to metro line 2 to Gulou Dajie, where transfer to line 8 to get off at Olympic Sports Center. Get out from exit B2 and you can walk there in 1,000-1,200 meters.

Apart from that, here is a much more convenient way to go: walk from the hotel to any terminal of the airport to take shuttle bus line 5 to get off at Asian Games Village (Anhui Bridge). Then ur destination is around 650 meters away.