The invention discloses a motor-home-carriage transverse inertia buffering method. When a motor home generates transverse inertia during turning, a carriage drives a supporting beam to generate pushing force to one side of the motor home, and hydraulic oil in hydraulic cylinders suffers from pressure of a hydraulic piston, is output to buffering oil cylinders and compensating oil cylinders through oil ways, and can enter the buffering oil cylinders; a supporting beam on the other side of the motor home can generate pulling force to the hydraulic piston, and under pulling force of the hydraulic piston, negative pressure is formed in hydraulic cylinders of the side, and oil liquid in the compensating oil cylinders can be only pumped to compensate negative pressure. Compared with the prior art, when the motor home suffers from transverse inertia in the driving process, due to oil liquid outputting and compensating between the hydraulic cylinders and the buffering oil cylinders and the compensating oil cylinders, the carriage has the micro transverse displacement, and is buffered, and the using comfortable degree of the motor home is guaranteed.