The invention discloses a rapeseed substrate block seedling transplanting device. The device comprises a rack, a driving rotating shaft, a chain wheel, multiple seedling delivery side plates, a seedling pushing device, multiple main seedling delivery plates, multiple seedling separating devices and multiple seedling taking devices, wherein the chain wheel is arranged on the driving rotating shaft,the seedling delivery side plates are uniformly arranged on the rack side by side, the seedling pushing device is located above the seedling delivery side plates, the main seedling delivery plates are connected with the driving rotating shaft separately, the seedling taking devices are connected with a seedling taking shaft separately, the number of the seedling delivery side plates, the number of the main seedling delivery plates, the number of the seedling separating devices and the number of the seedling taking devices are all equal, and the seedling delivery side plates, the main seedlingdelivery plates, the seedling separating devices and the seedling taking devices are arranged correspondingly one to one; the end side of an opening of each seedling delivery side plate is in butt joint with the corresponding main seedling delivery plate, each seedling separating device is arranged on the tail end of the corresponding main seedling delivery plate, and each seedling taking deviceis located above the corresponding seedling separating device. The rapeseed substrate block seedling transplanting device has the advantages that seedling delivery, seedling separating and seedling taking planting of rapeseed substrate block seedlings can be completed at a time, the device is suitable for seedling raising and transplanting of cube substrate blocks of different sizes in a certain range, bowl bodies are not consumed during seedling raising, and the work cost can be saved.