The invention provides an elastic cylindrical pin assembly tool which comprises a body and an ejector pin doing vertical guide movement relative to the body. A work cavity which coincides with the axis of the ejector pin and is used for containing elastic cylindrical pins is formed in the body. The body is further provided with a storage bin which is communicated with the work cavity and used for storing the elastic cylindrical pins. The storage pin is provided with a storage bin outlet which is communicated with the work cavity and allows a single elastic cylindrical pin to pass through. A pushing block is arranged in the storage bin. A pushing spring which is used for providing elastic force for the pushing block and enables the pushing block to push the elastic cylindrical pins in the storage bin into the work cavity from the storage bin outlet one by one is further arranged on the body. The elastic cylindrical pin assembly tool is convenient to use and can achieve continuous assembling; meanwhile, the human hands are not likely to be crushed, and safety is improved.