In a ideal world, people lived rich, happy, homonious and health, i believed the crime in society would be extremely low since the majority of people's desire were fulfilled. However, people could not live in a wonderful environment and the resourse distribution would not be the same in reality, it then induced people greedy. The increasing in crime rate in the city mostly comes from the poor living condition and the mentally illness for the people, relieving the situation is the way to help people out of trouble as well as enhancing social harmony. Finally, the crime rate will natually decreased.