Quantitative analysis on environmental impacts resulted from CTF and CTP plate-making technologies of offset printing enterprises in Dalian area was carried out by using life cycle assessment. The types, severity and causes of the environmental impacts generated by the two plate-making technologies were pointed out. Environmental benefits of the CTF and CTP were compared and evaluated by combing with relevant economic indicators, and the improvement suggestions were put forward. The research results showed that the environmental impacts caused by CTP process are relatively small, the CTP's environmental impacts in total is 83% of CTF's; however, green ratio of CTP to CTF is only 0.88, which shows that the environmental benefit of CTP technology is still at low level; control of power consumption, improvement of energy efficiency and reducing cost of printing plate are important ways to improve the environmental benefit of the plate-making technology; when internal cost of the CTP is cut down more than 15%, the CTP's market competitiveness can be greatly enhanced.