Abstract: The implicit related-party transaction has its own particularity on the background of Chinese listed companies. It has strong significance of study the implicit related-party transaction. The study thinks that the related party transaction within the group of decrease implicit transaction costs but increased the cost of small shareholders. Hidden costs have stronger influence on hidden related party transactions. Hidden costs increase agency costs but the relationship between the hidden costs and the size of related party transactions is uncertain. So it is necessary to distinguish related-party transactions from the point of normative research.