The invention discloses a road tunnel ventilation testing device comprising a tracer gas inlet device, an organic glass tunnel, an axial flow fan, a wind velocity indicator, a CO detecting instrument and a baffle plate, and is characterized in that the organic glass tunnel comprises two adjacent tunnels and is made of organic glass in segments, the axial flow fan is a ventilating device, the flow fan is connected with the organic glass tunnels, the wind velocity indicator is a wind velocity measuring instrument, the wind velocity indicator is positioned at the air outlet mouth of the organic glass tunnel, the CO detecting instrument is a tracer gas measuring instrument, the CO detecting instrument is positioned at the air outlet mouth of the organic glass tunnel, the baffle plate is positioned between the air inlet end and the air outlet end of the organic glass tunnel, and the tracer gas inlet device is connected with the first organic glass tunnel. The testing device in the invention has the advantages of low cost, good ventilation, simple structure, convenient and easy test, stable and reliable testing result, and the like.