Flow conservation equation and pressure balance equation of doubleshaft blow and exhaust ventilation model for highway tunnels are recommended on basis of hydrodynamics in the paper. The dichotomy algorithm is adopted to extract the numerical analysis of the flow conservation equation. Furthermore, the initial trial value and constraint conditions of the algorithm are discussed. Based on the above dichotomy algorithm, a calculation program for the ventilation system consisting of doubleshaft blow and exhaust model integrated with jet fans has been developed by using a robust objectoriented programming language called Visual Basic for Application (VBA). The calculation program has been applied in the design of the ventilation systems of several highway tunnels and satisfactory effect has been achieved. Finally, the countermeasures to improve the economic efficiency of the ventilation system are presented in respect of economic air velocity and equipment control.