No.2, 1, Line 4. According to Baidu map, it is estimated that it will take 36 minutes to take subway lines 2, 1 and 4 from Sanyan subway station to Xi 'an station and walk 260 meters, with a total distance of 12.4 kilometers. The specific route is as follows:

1. Walk 10 meters to Sanyan Station, take Metro Line 2 and get off at Beidajie Station.

Secondly, take the subway 1 line at Beidajie Station and get off at Wulukou Station.

Then walk 770 meters and change at the station.

4. Take Metro Line 4 at the last Wulukou Station, get off at Xi 'an Station (Exit C) and walk 190 meters to Xi 'an Station.