Abstract: Commission has existed for a long time. Due to the lack of regulation of commission by law in our country, both academic circle and practice field have not reached agreement on the nature, effect and money return of commission. From a perspective of civil law, the commission should be taken as a contract and brought into regulation by civil law. As for its effect, the court should follow the judgement rule of civil juristic acts and make a judgement according to the 16^th and 17^th articles of Interpretation of Contract Section of Civil Code. In terms of money return, the court should distinguish the valid commission from the void one. Especially when the commission is invalid, the court should deal with the money return according to the evidence and degree of both parties’ fault.