Abstract: The gas wall heater has been widely used in recent years because of its better economic benefit and social benefit compared with the traditional heating modes. Most of the gas wall heaters accepted by consumers in China are produced by European countries, therefore the heaters which are popular in the markets are de-signed for natural gas. One of the important problems which appeared during the process of product promotion and utilization is the matching problem between the gas resources and the gas heater designed for natural gas. The relationship between gas property and fire hole diameter of gas heater was discussed based on the Huabai number and interchangeability between natural and artificial gases.