Regarding front-wheel drive passenger car, because of the limit of power transmission system space, a torque converter was developed to the flat shape. In this paper, a leaned blade flat torque converter was developed with an increasingly narrower torus's profile for the purpose of achieving a smaller axial size. It is composed of a pump having a leaned pump blade, a turbine having a leaned turbine blade and a stator, and the flatness ratio is 0.21. The core of the pump blade's inlet and outlet is opposite separately in the shell and moves 1/3 cascade spacing along the pump's hand of rotation. The core of the turbine blade's inlet and outlet is opposite separately in the shell along the turbine revolving and go astern 1/3 cascade spacing. The computational results indicate that the torque ratio decreases slightly but the torus is more flat when the blade is leaned. And the capacity factor decreases, the nominal torque improves, it may use the small effective diameter to satisfy the match request of passenger car with the same engine power, and it has more vital practical significance to solve the question of front-wheel drive layout's limit.