A novel method is proposed to determine the unknown organic compounds by measuring the combustion heat based on non-linear regression analysis. According to the combustion heat determined using oxygen bomb calorimeter, the equation of determination can be transformed into the determination of Q/M value. After the Q/M value is calculated by means of the equation, we used nonlinear least squares data-fitting method to obtain a best fit curve and to predict Q/M value. Levenberg-Marquardt algorithm is used during the fitting process. On the basis of the accomplishments above, we designed software called Organic Predictor that can quickly and easily determine the unknown organic compounds.