Based on the contrasting analysis of environment and natural resources' value,the author distinguishes two sets of concepts,i.e.environment and natural resources,and environment rights and natural resources rights.Then the author demonstrates that regulating object,basic content and central issues of environment law and natural resources law are not the same.So the system of environment law and that of natural resources law are independent.Because environment and natural resources are nearly interrelated,environment rights and natural resources rights are relatively independent,so the system of environment law and that of natural resources law are not absolutely independent.The author makes a further study on theory and realistic basis of oneness of environment law and natural resources law,the name,conception and system's readjustment of combined department law.