Western scholars considered that th e development level is the main crite ria to distinguish soft science and hard science.A public survey supports this idea.The conception of soft s cience was developed in China since 1980s and has been stabilized in emphasizing the complicated research object,synthetic research method and the su pport for decision making by research achi evement.This is similar to the understood conception of the western scholars and the public.Applying the notion of fr actional graph area(FGA)it is possible to distinguish soft sc iences from hard sciences.The same is applied to the s ub -disciplines.