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As more and more concern was paid on the Naturally Occurring Radioactive Materials (NORM) in coal-fired power plants (CFP),studying the radiation release from CFP and evaluating the radiological effects to the environment is a far more important issue in recent years.In this work a stack sampling instrument was developed to sample the aerosol radionuclides from the CFP.Based on the sampling instrument,a 225-MWe costal coal-fired electric utility plant was sampled to determine radionuclide concentrations in all major process streams including coal,fly ash and bottom ash samples and six naturally occurring radionuclides: 238U,226Ra,210Po,210Pb and 230Th and 232Th were analyzed by gamma spectrometry and alpha spectrometry.Of all radionuclides studied,210Po is the most volatile elements; therefore,an increase in the natural radiation level should first be indicated by an increase of this nuclide.For this plant,radionuclide balances were computed and the emission amount of aerosol Po-210 in the stack effluent was determined and the amount of aerosol Po-210 emitting from stack was normalized by the total electric power of the CFP and it was found that about 2.5682E+8Bq/GW/year of Po-210 was released into environment from this costal CFP.In this work,a thorough literature review was made for studying the chemical and physical character of Po-210 in the high temperature so as to obtain the depositional model and distribution of Po-210 in the boiler system of CFP.In this work,a measurement technique measuring the Po-210 in the sea water also was developed and the Po-210 in the desulfurization wastewater was analyzed and it was found that the concentration of Po-210 in the desulfurization wastewater was an order of magnitude higher than the normal sea water.In this work the micro morphological of the aerosol Po-210 from the stack was analyzed by scanning electron microscopy (SEM) technique and a preliminary method for distinguish the source of aerosol Po-210 in the air around the CFP was developed based upon the SEM technique.