Liquid rocket engine is an important member of the space propulsion family and the only propelling means to bring payloads to the first universe velocity in the next historical period, which has vital effects on advancement of space technologies. Propulsion must enjoy priority in research and development of launch vehicles. In the early part of 21st century, China should successfully develop its heavy lift launch vehicles equivalent to that of other advanced countries in the world. We won´t allow them to set up on the bases of simply increasing number and thrust magnitude of existent engines and must develop new types of engine which are more powerful, more advanced and without contamination. Meanwhile, we should begin preliminary researches on rocket spaceplane and aerospike nozzle adopted by it´s propulsion. Along this way, we can finally catch up with the world´s advanced level.