Mathematical modeling is the process of designing a model of a real system and conducting experiments with it for the purpose of understanding the behavior of the system. Mathematical simulation is widely used for investigating and designing the compressors. Investigations of the processes of reciprocating compressors using mathematical models is an effective tool by high development of computing technique, which enables complicated problems to be solved with a minimal number of simplifying assumptions. A considerable number of previous works has been done on the mathematical modeling and simulation. The aim of the present work is to construct a model which is easy to understand, easy to detect errors in the process of building a model, and easy to compute a solution. This paper presents a simplified and effective mathematical model for the estimation of reciprocating compressor performance using personal computers that can be easily handled. The effect of operating parameters, speed and discharge pressure on thermodynamic behavior of compressor in working condition has been analyzed. The model has been developed for obtaining cylinder pressure, cylinder volume, cylinder temperature, valve lift and resultant torque at different crank angles and free air delivered and indicated power of the compressor. The model has been validated using experimental results.