A new Gas Flow Sensor was derived from the current air flow sensing technology. This sensor is targeted at measuring the amount of gaseous mass flow under high pressure and with varying gas temperature.Thermodynamical properties of CH4, air, N2He and CO2 have been compiled at different pressures and temperatures. This information is required for the simulation.A theoretical model has been developed to analyze the behavior of the sensor circuit with different gases at varying pressure and temperature. The theoretical model encompasses a model of the gas flow circuit as well as a flow model with an optimized fluid dynamic equation.Fluid dynamics have also been studied to demonstrate the usage of a bypass and a mesh screen for flow regulation. A finite element analysis (FEA) is also generated to study the velocity profile and potential turbulence areas.