A three-node trust experiment which contains one principle and two agents is designed on the basis of the BDM trust game． Experimental results reveal that principals send more to agents in the three-node trust game than in the two-node trust game，and the amount sent to both agents are equal in order to diversify risk． Besides the game structure，the principals’risk preference and the family environment also have a significant influence on trust behavior． After all，the total efficiency of the three-node trust game is higher than that of the two-node one，though the trustworthiness of the receivers in both two structures is almost the same．