The inflorescence development of Black Queen (Vitis vinifera L.×Vitis labruscana Bailey) grapevine was investigated after inflorescence treated with various concentration GA3 and Fulmet at the 4th leafing stage. The results showed that the inflorescence elongation could be enhanced by GA3 treatment. Fulmet promoted the size of the floret and ovary. Under the same concentration treatment of GA3, the inflorescence length, fresh weight of floret and ovary of the second harvest were lower than that of the first harvest. Based on the result, the suggested optimum concentration for GA3 treatment was 10~25 ppm, combined with Fulmet at 5~10 ppm.