The Chinese government has strengthened the crackdown on corruption as well as business bribery in the field of economy after the 18th National Congress of the Communist Party of China. Combating business bribery needs the cooperation inside and outside of companies, and internal audit is a vital means of internal governance against business bribery. Real estate industry is believed to be one disaster zone of business bribery. Taking listed real estate company, Shimao Group, as an example, this paper tries to find out whether the company has subjective motivation to manage business bribery with internal audit. The finding is that companies would pay attention to internal audit against bribery taking by employees if these behaviors could damage the corporate benefit, especially in major companies as they have higher agency costs. So agency theory can explain the root cause of internal audit against bribery taking. The pursuit of legality and success acting as “a soft constraint” in reputation will reinforce the company’s motivation of antibribery internal audit. So institutional isomorphism theory could provide an assistant explanation. Finally we propose how to enhance the enterprise motivation of internal audit against bribery giving.