Vertical take-off and landing (VTOL) aircraft not only has the ability of vertical take-off and landing like helicopter, but also be provided with high-speed cruise capability as traditional fixed-wing . Aircraft. VTOL is one of the hot spots of research in both military and civilian unmanned aerial vehicles. In this paper, a new layout, tilt-tandem wing and quadrotor of VTOL aircraft, is proposed to avoid the defects of .low aerodynamic efficiency and complicated tilting mechanism. Conceptual design and aerodynamics simulation also have been carried out. the aerodynamic characteristics of aircraft with the interference of propellers Further more, prototypes are made and experienced several flight tests validation. The flight tests validation shows that this layout can avoid the disadvantages of low efficiency propellers and complicated tilting mechanism,which is reliable and practical.