The magnetic coupler plays an important role in wireless power transfer(WPT) system and concerns the transmission efficiency and output characteristic of system. The effects of asymmetric two-coil and three-coil magnetic couplers with a large intermediate coil on lateral misalignment tolerance for WPT system are studied. First, circuit models of two-coil and three-coil magnetic couplers are analyzed and the key parameters affecting the efficiency of two-coil and three-coil coupler are deduced. Then, a 3-D finite element model of the two-coil coupler is established, and the efficiency of WPT systems with two different structures is investigated while misaligning. Finally, the applicable conditions of two coil structures are discussed. The results show that when the maximum misalignment distance is reached, the misalignment tolerance effect of two-coil structures is weakened, and the system efficiency can be higher by using the three coils structure with a large intermediate coil.