Disclosed are a method and a system of device-to-device tunnel establishment between small cells, applied to a wireless backhaul management device, a first small cell and a second small cell. The method comprises: matching the first small cell and the second small cell according to a first discovery response and a second discovery response; submitting a match report; replying with a match report response; conducting a D2D connection authentication procedure between the second small cell and the first small cell; wirelessly connecting the second small cell and the first small cell, conducting a connection test and submitting a connection test report; replying with a D2D tunnel establishment decision according to the connection test report; and establishing a D2D tunnel between the second small cell and the first small cell.