The earth scale changeof climate has brought a new kind of natural disaster and the developed andcomplicated city system is holding a latent risk of expanding the damageartificially. Also people has been spoiling the health since theimmense quantity of chemicals have been produced and already used in pursuit ofconvenience and various toxic substances have been producedunintentionally and accumulated in environment. Therefore, We need somecountermeasures from the viewpoint to prevent the city environmentform disaster and to manage environmental risks. So we will developand improve a new risk management system and a disaster prevention system topreserve and create the city environment where people feel easy and sound intheir life.