The background of developing large commercial aircraft was given.The hydraulic power systems of popular and new type commercial aircrafts from Airbus and Boeing Company were introduced. The future trends of hydraulic system for civil aircraft were outlined, namely high pressure, distributed system,DPHM(diagnostics,prognostics and health management),boostrap reservoir and intelligent pumping source system. The hydraulic power systems of A320
and B737 were compared and the two proposals of hydraulic power system for China commercial aircraft were brought forward. The key techniques of developing commercial
crafts, namely high reliability, pressure pulsation control, temperature control and contamination control were indicated.