Abstract: New liberalism is in global expansion, shaking the theoretical foundation of welfare economics, making' the welfare system challenged too. I, proceeding from technological value theory, try to analyse "paddy field phenomenon" of the social security. Theoretically an appropriate social security helps to guarantee the society by justice and improving economic efficiency. China's low social security has already influences on the by justice and economic development of the society seriously. So we must strengthen and reform the Chinese social security system in a more effective manner