The soil and water cx>nservation in loess plateau region is a systems engineering which contains two subtechnical sustenance system and social security system. But for a long time past, since lacking thorough analysis on the social security system many discordant problems have appeared between the two parts which restrict the developm-ent of soil and water conservation. Ther, fore, it is particularly important to stre-ngthen and improve the social security system. From this meaning, the conception, the reasonable system structure and virtu-ousmworking of the socialsecmity system areinquired into. It is pointed out that in this system the macroz}ontrol,policy and action of government are the key factor. And also,the main way and significance to improve the social security system are discussed.