A reduction system for particulate materials in exhaust gas, which is connected to a tailpipe of an engine that burns a hydrocarbon-based fuel supplied from a fuel storage tank, and collects and removes particulate materials within the exhaust gas, may include a plasma reactor having a gas inlet and an outlet, and a DPF (diesel particulate filter) trap having a filter. The tailpipe of the engine may communicate with the gas inlet of the plasma reactor, and the outlet of the plasma reactor may communicate with the DPF trap. The exhaust gas exhausted from the engine may be transferred to the DPF trap after being heated while passing through the plasma reactor.