, overpopulation is an undesirable condition where the number of existing human population exceeds the carrying capacity ofworld. Overpopulation is caused by a variety of factors. Overpopulation is among the most pressing environmental problems. In the present, Medical profession have a up to date tool therefore It makes people sick or dying less. Human overpopulation is effect to anything that the people can not know before. The most people of world want to have a lineage. The passage of time for many years population increases. Also, the people get more poverty and more difficulty. We should to control about over population. If people can not help together, it will be bad result or disadvantage , Such as fully inhabited city and depression. The Three main cause are High Cost of Living , Global Warming , species extinction.