As a result of energy and materials consumed by diverse human activities, a great deal of green house gases had been discarded and emitted into the global atmosphere. The GHGs (green house gases) make the earth warming, climate abnormality, bio-system changing and even destroy the stability of agriculture product and food. Because of export trading, the high technology industry is the main driving force of economic growth in Taiwan, R.O.C. The wastewater treatment plant of high technology industrial park should obey all GHGs inventory and reduction protocols to avoid the boycotts from international GHGs alliances. There are five main issues about GHGs emission of high technology industry wastewater treatment plant in this research . First of all, the empirical formula of microbial cells was proved by elementary analysis and stoichiometry calculating; accordingly, the overall reactions for biological expiration and biomass growth equations was induced by bacteria kinetics and mass balance with an assumption of glucose acting as a reactive substrate of influent. Then, the GHGs on-site emissions can be evaluated in accordance with the dairy data of aerobic wastewater treatment plant, such as the volumetric flow rate, BOD, COD , SS and sludge output, etc. The GHGs on-site emission of high technology industy wastewater treatment plant in 2012 ranges from 1,317,437 to 3,108,635 Kg CO2(e). The GHGs off-site emissions are 6,994,659 Kg CO2(e) estimated by the inventory of electricity, alkalinity, flocculation reagent and sludge transportation, etc. The overall GHGs emission ranges from 8,321,822 to 10,113,020 Kg CO2(e).. Biological expiration and biomass growth reaction, emitted about 56~64% of all the GHGs on-site emissions, is the major GHGs on-site resource. Otherwise, electricity comsumption, emitted about 69.9% of all the GHGs off-site emissions, is the major GHGs off-site resource. Secondry, high technology industy wastewater treatment plant is going to establish a A2O(Anaerobic-Aerobic/Anoxic ) hybrid bio-reaction system to ensure the quality of effluent meets the new public ammonia criteria. The new biological stoichiometry equations , on-site and off-site GHGs emissions have been demonstrated in this research with an assumption of biomass yield from textbooks. The GHGs on-site emissions of anaerobic hybrid treatment system are 24,274,999 Kg CO2(e). The GHGs off-site emissions are 12,212,272 Kg CO2(e) estimated by the inventory of electricity, alkalinity, flocculation reagent and methane, etc. The overall GHGs emission are 36,487,271 Kg CO2(e).. The third, the residual organisms and ammonia of effluent decomposed and emitted the GHGs in the recevier. The emissions for aerobic and anaerobic hybrid treatment systems are 9,154,291 Kg CO2(e) and 3,791,185 Kg CO2(e) respectively, in accordance with the emission factors from literatures. The fourth, the different sludge treatments, such as landfill or incinerating, may cause significant environmental impact of GHGs and has been evaluated. The GHGs emissions through landfill and incinerating for aerobic treatment systems at present are 11,757,681 Kg CO2(e). Otherwise, the GHGs emissions by incinerating for anaerobic hybrid treatment systems are 9,054,760 Kg CO2(e), reducing 63.3% of landfill emissions. The fifth, the GHGs reduction benefits was also estimated to establish a set of sludge anaerobic digestor and electricity generator for methane reuse in high technology industy wastewater treatment plant. Comparing with the landfill, the GHGs reduction through a sludge anaerobic digestor of the aerobic and anaerobic hybrid treatment systems are -23,240,100 Kg CO2(e) and -33,928,285 Kg CO2(e) respectively. The reduction ratios are -101.9 % and -137.6 % accordingly. The performance of GHGs reduction of the sludge anaerobic digestor is very distinguished.