how much will cost for taxi from PEK airport to the St. Regis hotel in Tianjin

If taking a taxi, the fare is about CNY400-500. Actually, you have a better choice. In the airport, there are direct buses to Tianjin. The bus duration is about 2.5 hours, and the fare is CNY82. The bus will arrive at Tianhuan Bus Station. Upon arrival, take a taxi to the hotel at a cost of CNY15-20.