A method for manufacturing an organic electroluminescent display device is provided, which includes the steps of: providing a lower support substrate and an upper support substrate; making a lower flexible substrate and an organic electroluminescent device layer on the lower support substrate sequentially, making an upper flexible substrate and an adhesive layer on the upper support substrate sequentially; aligning the lower support substrate and the upper support substrate, to thereby attach the adhesive layer and the organic electroluminescent device layer; and peeling the lower support substrate and the upper support substrate. An organic electroluminescent display device made by the above manufacturing method is also provided. Accordingly, it can effectively solve the separating problem of a rigid substrate (a support substrate) and a flexible substrate, and the organic electroluminescent device is packaged directly in the manufacturing process, without additional thin film packaging device, therefore the manufacturing cost is greatly reduced.