Tianjin Airport has shuttle bus to Beijing Bawangfen Bus Station in Dawang Road: about 2.5 hours leaving from Tianjin airport at 10:00、14:00、16:00、17:00、19:00. Bawangfen Bus Station is only about two subway stops from the hotel you are heading to, within 4 km by taxi. So, suggest you just take a taxi or you should walk to Dawang Road subway station and then to the hotel from Jianguomen subway station.