The blow and exhaust ventilation is the most popular scheme in extralong highway tunnels at present. The functional characteristics and applicable conditions of different longitudinal ventilation modes are analyzed in terms of design. The ventilation mode of singlechannel complementary ventilation is proposed based on the study of characteristics of blow and exhaust ventilation and complementary ventilation. By taking Jinmen Extrolong Highway Tunnel for an example, four ventilation schemes, i.e., blow and exhaust ventilation, single channel complementary ventilation, doublechannel complementary ventilation and dust collection ventilation, are compared and studied from the view of life cycle. The main conclusions are drawn as follows: (1) The position of ventilation shaft has a great influence on blow and exhaust ventilation system, it should be set in the downstream direction of the middle part of the uphill tunnel. (2) Complementary ventilation and dust collection ventilation do not consinder the location of ventilation shaft; for tunnels over 5 km, special exhaust shafts should be set. (3) Singlechannel complementary ventilation does not need the ventilation shaft and retains the function of exhaust smoke, which is worth considering in scheme comparison.