After Western Development, economic growth is accelerated and people’s living level is raised in western areas, however, industrial structure, technical level and ecological environment quality are not improved and raised at the same level. This paper uses 30 provincial panel data in China from 1995 to 2011 based on the PSM-DID method, and makes core empirical analysis. The results show that while Western Development boosts economic growth in western areas and regional economic convergence, the Policy makes the carbon emission in western areas, especially per capita carbon emission, grow more rapidly than other regions, meanwhile, the related factors and conditions in western areas, for example, industrial structure, technical level, marketization and so on, are not significantly improved. Under the existing resources endowment, development stage, industrial structure and economic development mode, at initial period, western development focused on the investment of fixed assets and energy development but ignored the soft environment construction such as regional education, marketization reform and technology innovation, which led to economic booming but carbon emission increasing relatively. Therefore, in the following western development, western areas should transform the economic development mode, enhance soft environment construction, pay attention to human capital accumulation and technical innovation, raise marketization level so that energy conservation and emission reduction can be realized while western regional economy is developed.