The article is generally pointing out the importance of professional ethics in different jobs and specifically its important role in small businesses. By providing a definition of entrepreneurship and small businesses, we have tried to distinguish the border between them. Then by classification of the research on the ethics of entrepreneurship companies firstly the ethical approaches of entrepreneurs, the ethical issues before the entrepreneurs, ethical decision making of entrepreneurs, owners of small businesses and customers and type of entrepreneurship activity were discussed and finally the article ended by a conclusion and proposals in the form of taking five important steps for the promotion of professional ethics in business environments.