Crude oil is the one of the most important energy resources in the world and its prices have fluctuated widely, especially since the early 1980s. However, the higher oil price will exert upward pressure on the inflation rate in the world and thereby damage the global economy. Thus,in this paper we investigate the oil demand, oil price as well as environment Kuznets curve. In chapter 2, we attempt to use panel fully-modified OLS approach to example the crude oil demand in Asian countries over the period 1971-2005. In chapter 3, we attempt to use panel unit root and panel cointegration tests as well as the fully-modified OLS approach to examine the relationships among carbon dioxide (CO2) emissions, energy use and GDP for 22 OECD countries (Annex II Parties) over the 1971-2000 period. In terms of the EKC hypothesis, the results showed that a quadratic relationship was found to exist in the long run. Thus, other countries could learn from the developed countries in this regard and try to smooth the EKC curve at relatively less cost.