Abstract: A simple but efficient method is put forward to predict the basic parameters at the plasma gun nozzle exit,especially for typical Ar-He plasma spray processing.By measuring a serial of input powers and related currents,primary gas flow rates,as well as secondary gas flow rates,a linear mathematical model is established.Using the law of energy balance,the plasma temperature at the nozzle exit is calculated,and is further used to calculate the plasma velocity by solving the gas state equation.The results are in good agreement with experimental observations.The methodology adopted overcomes complexity and uncertainty of traditional methods,and are theoretically helpful for guiding the plasma spraying processing.