Take a taxi or take a a bus called Aerobus1 or Aerobus2 to Plaza Catalunya. In Plaza Catalunya take the Ferrocarriles Catalanes, Line 7 (direction Tibidabo and get off at station Putxet) or bus number 58 and get off at Plaza Bonanova.
Bus lines: 14, 16, 17, 22, 58, 64, 70, 73, H6, 75, N0 and N8.