This paper analyzes the urban vulnerable groups in house needs, as well as housing security policy; the conclusion is to carry out low-rent house system. Furthermore, the shortcoming lies in system, fund, object, quantity and information nowadays is pointed out. The countermeasures perfecting the low rent house system are presented. There is a strategy named "helps to others and oneself" to realize a policy that the powerful and the vulnerable groups must have symbiotic development, to form steady normative source of insurance fund, to play an effective role in low rent house stock, to establish managerial mechanism which all the departments are on duty, to build system from low rent house application to its supervision, to take the manner of rent allowance, to perfect correlative policy of low rent house and house security.