A vacuum condition processing apparatus is provided, the top of which is connected to an external charged particle beam generating device, and the apparatus includes: a suction cup in contact with the specimen to be observed or the stage holding the specimen, a first gas controlling device connected to an external gas supplying system, and a second gas controlling device connected to an external pumping system; a window is deployed at the top of the apparatus, through which the particle beam can go into the apparatus; the first gas controlling device is arranged to connect the gas supplying system and the suction cup; the second gas controlling device is arranged to connect the gas pumping system and the suction cup. Also disclosed is a specimen observation system and method.