biomass　energy　is　a　kind　of　renewable　energy.　Biomass　pyrolysis　technology　is　an　effective　way　to　convert　biomass　energy　into　combustible　gas　and　biochar.　Aiming　at　the　problems　of　low　gas　production　rate,　poor　quality,　low　automation　level,　difficult　to　control　furnace　temperature　and　high　energy　consumption　in　the　process　of　biomass　gasification.　This　paper　introduces　an　automatic　control　system　of　biomass　pyrolysis　gas　carbon　compound　furnace　based　on　PLC.　The　system　uses　PLC　as　the　lower　computer　and　MATLAB　software　as　the　upper　computer.　It　uses　neural　network　and　fuzzy　algorithm　to　process　the　data　in　the　process　of　operation,　and　adjusts　the　parameters　in　the　lower　computer　on　line.　WINCC　software　is　used　to　monitor　the　running　process　and　realize　human-computer　interaction.　The　automatic　control　is　realized　and　the　utilization　rate　of　biomass　energy　is　greatly　improved.