In this work we have investigated the ,60,Co gamma ray response characteristics of polymethy methacrylate piece, cellulose triacetate, polystyrene, polyvinyl alcohol, polycarbonate and polyethylene terephthalate films, which can be commercially supplied in chinese market.,The absorption spectrum and the wavelength of optical absorbance reading, dose range and precision limits for these clear plastic films are studied. The effect of dose rate and stability of system after irradiation have been illustrated. The effects of temperature and relative humidities during and after irradiation on dose interpretation of this dosimeters are examined. The calibration curves are given under controlled experimental condition. The results show that cause for limited prepecision limits in these dosimeters vary in the thickness of the sensor, the dosimeter reseponse with differences in production batches or in lots supplied by different manufacturers, the environmental conditions, the dose rate denpendence, and the unstability in the systems after irradiation. Hence, when these plastic films are used for routine dosimetry in radiation processing with gamma radiation, the quality of materials must be selected, the thickness of films must be carefully monitored, and the calibration curves must be made under experimental conditions. Except for the polyvinyl alcohol film, others can be satisfied.,The polymethyl metharylate piece and the cellulose triacetate film with different thickness are suitable for the doseage from 0.1 Mrad to 100 Mrad. For above 100 Mrad, the polycarbonate film and the polyethylene terephthalate film can be applied. But because polyethylene terephthalate film has strong dose rate dependence, the polycarbonate film should be used below 500 Mrad.