On the basis of developing 3mm Dicke radiometer,a set of 3mm radiometric imaging system controlled by PC-MCU mode was presented.To solve the contradiction of sensitivity and spatial resolution for the motion platform imaging system,the software integrator was designed and the cascade system integration formula was derived.Furthermore a morphological composite filtering was used to improve the imaging resolution.The experimental results show that 3mm radiometric images spatial resolution is superior to 8mm images' and the processed image can wipe off noise effectively.In addition,it is verified that the software integrator can take place of the hard integrator in some degree.The radiometric parameters are given below: the center frequency 94GHz,the sensitivity 0.2K,the linearity 0.999,the system bandwidth 2GHz,the cassegrain antenna 3dB beam width 0.5°.