Paris Agreement and the decisions of Paris climate conference require parties to communicate their long-term low emission development strategy. This paper analyses the long-term strategies of 12 countries in terms of legal effectiveness，target strength，and emission reduction pathways of greenhouse gas emission sectors. Generally speaking，the European countries have better legislative basis，stronger legal forces and relatively guaranteed enforcement. Legislation at the national level in the United States and Canada is relatively lagging behind，but policies and actions at the sub-national level are relatively positive. The high-profile participation of small island countries in global climate governance has sent a signal of increased action to the international community. From the point of view of emission reduction，developed countries generally put forward the quantitative emission reduction target as high as 80% by 2050，with detailed sector decomposition. Long term strategies of developing countries is weaker in terms of mitigation action in accord with their national circumstances. The conclusion is that the long-term strategy should be well integrated with the national conditions，capabilities and development priorities of each country，Early submission can set out a positive role and show the international community its positive attitude in combating climate change. On the basis of adhering to the position of developing countries，China should display the image of a responsible big country and strive to submit a long-term low-emission development strategy of greenhouse gases by 2020.