Abstract: This paper introduces the parameter estimation research for the turbine inlet temperature and compressor exit pressure by using the engine variables measured under the different flight conditions.The parameter estimation method is multiple linear regression analysis.The independent variables in the regression equations have been selected from six measured engine variables based on the comprehen sive optimal principle about variable selection.The regression models which have been established only include three measured engine variables.The curves of the parameter estimation results shown in this paper demonstrate that the estimation accuracies of these mode ls are satisfactory.This paper also presents the data treatment meth ods of engine variables recorded on line with special equipment.