Abstract: The broad and deep impact of business ethics on the economy and society makes enterprises unable to avoid the existence of ethics; its orientation function to economy and the dominant role in economic behaviors are significant and outstanding. The advantage of business ethics will form the ultimate advantage of sustainable development in the enterprises. The ethical thoughts revealed in the welfare economics, neo-institutional economics, Marxist economics and ecological economics demonstrate the necessity of business ethics for the sustainable development of enterprises, which offers the enlightenment for the construction of business ethics.

Key words: economics; ethical thought; business ethics