The invention relates to a flat arrangement structure of a hybrid power cross-country vehicle assembly, belonging to the technical field of electric cross-country vehicles. The structure comprises a left front electric wheel, a right front electric wheel, a left rear electric wheel, a right rear electric wheel, a left front double-wishbone independent suspension, a right front double-wishbone independent suspension, a left rear double-wishbone independent suspension and a right rear double-wishbone independent suspension, and also comprises a high-rotation-speed diesel engine and a permanent magnet synchronous generator assembly, wherein the high-rotation-speed diesel engine and the permanent magnet synchronous generator assembly are longitudinally arranged at the front part of a chassis frame assembly; and each of the left front electric wheel, the right front electric wheel, the left rear electric wheel and the right rear electric wheel is integrated by a four-wheel distributed hub motor, a planetary reducer, a brake and a wheel. According to the invention, hub motor driving systems are directly integrated at wheel ends, so that the arrangement of an entire vehicle is very simple, and the height of the center of gravity of the entire vehicle can be further reduced on the premise of keeping high cross-country performance so as to improve the running stability of the vehicle.