Aiming at the need of cost control in the development of civil aeroengines, this paper studies the cost estimation method of civil aeroengine in order to estimate quickly the cost of civil aeroengine development when establishing model demonstration. In the study, combined with the engineering practice, the important overall parameter equations of the engine were established. The correlation between engine parameters was analyzed, and several key characteristic parameters for establishing the parameter model to estimate the development cost were identified. Several engines’ development cost and key feature parameters were collected. A multivariate linear regression theory was used to establish a cost estimation parametric model, and regression significance test was performed on the model. Considering that the samples data used in this article are the cost data of civil aviation engine development from different foreign countries, the calculation results of this model require time correction and currency correction. The parameter model established in this paper is suitable for the rapid estimation of development cost in the early stage of development, and provides an important basis for project demonstration and cost control.