The invention relates to a road marking paint mixing device. The road marking paint mixing device comprises a loading mechanism and a conveying mechanism, wherein the loading mechanism comprises a loading device a and a loading device b, the loading device a is used for accommodating petroleum resin and the loading device b is used for accommodating addition powder; the conveying mechanism is arranged below the loading mechanism. The conveying mechanism comprises a transfer device and a material discharging device arranged below the transfer device, the transfer device comprises a transfer part a and a transfer part b, the transfer part a is used for transferring the petroleum resin accommodated inside to the material discharging device quantitatively in cooperation with the loading device a, and the transfer part b is used for transferring the addition powder accommodated inside to the material discharging device quantitatively in cooperation with the loading device b. With the adoption of the road marking paint mixing device, the problems that materials are required to be mixed in advance when a traditional road marking device is used, a large quantity of materials are hot-melted once and are required to be stirred constantly in use to avoid deposition, work procedures are increased, and efficiency is low are solved.