The invention discloses a fresh air system of a mobile operation car, which comprises a fresh air host machine and an air supply connecting pipeline, wherein the fresh air host machine is arranged in an operating room, and the air supply connecting pipeline is connected and interlocked with the fresh air host machine and the outside of the operation car. Compared with the prior art, the fresh airsystem of the mobile operation car has the following advantages that: 1, by setting the fresh air host machine, clean air at a constant temperature is ensured to be supplied to the operating room, and the clean air is bacteria-free and dustless; and 2, by using the special air supply connecting pipeline, fresh air is ensured to be further filtered and disinfected before entering the fresh air host machine so as to ensure the effect of supplying the clean air by the fresh air host machine.