In the assessment of radiation environment, the natural radiation dose decides whether it is necessary to apply the control for radioactive factor or not in concrete areas. Currently, many organs and agencies get involved in studying radioactive environment, but dose assessment methods are not consistent, leading to the different assessment, causing misunderstandings and difficulties for comparison between areas. In this article, the authors present methods for evaluating radiation dose components resulting from natural radiation sources in order to unify method for assessing and calculating natural doses of radiation.