It is widely accepted that, at present, the SO$_2$ emissions in China are not increasing thanks to the rigorous Chinese government policies. However, with the development of western China, it is possible that the SO$_2$ emission amounts might increase in regional scale. In this study, changes of sulfur deposition pattern and unprotected ecosystem in east Asia due to the sulfur emission pattern changes in China are studied by using the RAINS-Asia model. Five scenarios have been postulated to understand the effects on east Asia, especially, on Korea and Japan. It is found that the increase of SO$_2$ emission in western China might increase the total emission in whole China. And the amount of sulfur deposition from western China on east Asia would be higher than those from eastern China. The deposition amount of sulfur species on Asia is 3.2 Mt when SO$_2$ are emitted from western China only while 2.6 Mt from eastern China only. Generally, Korea and Japan are influenced more by emissions from eastern China than western China. However, if the SO$_2$ emissions from western China increase by 100% while those decrease by 10% in eastern China compared to the base case, the deposition amount of sulfur species on Korea and Japan would be higher than the base case. The fraction of unprotected ecosystem in Korea and Japan for the base case are 50 and 5%. However, if the emissions from western China increase by 100% while those decrease by 10% in eastern China, the fraction of unprotected ecosystem in Korea and Japan would be 52 and 6%.