In the process of urbanization, a great deal of collective land was expropriated and large number of farmers lost their land in the countryside. It is now the high time to establish a safe social security system for them. Great attention should be paid to the current system which is put into effect by many districts since there are many problems within. At the same time, we should foster social security system reform for lost land farmers under direction of such principles as system preceding, adjusting measures to local conditions, integrating equity with efficiency and linking up with the current system. At first, on account of the fact of our country, we should establish the social endowment insurance and social Medicare system, and then other social security measures should be taken step by step.