Biomass is the largest and the most important renewable energy source in the world. World production of biomass is estimated at 150–200 billion metric tons a year. Currently biomass provides approximately 14% of the total world energy consumption. The most effective way to convert biomass into energy is its conversion into combustible gas. However, the existing gasification technologies have several disadvantages. One of the most urgent problems of biomass gasification is cleaning the product gas from tar and carbon dioxide. Joint Institute for High Temperatures of the Russian Academy of Sciences suggests the gas cleaning technology based on the heterogeneous cracking of pyrolysis tar on the surface of the charcoal. In this paper the results of experimental determination of hot char filter parameters influencing on the efficiency of heterogeneous of pyrolysis tar cracking are presented.