  The double J/\psi(DJ) production in direct photon-photon collision is
investigated. It is found that the J/\psi production rate in this process is of
the same order of magnitude as those of previously discussed ones, which hints
the dominant J/\psi inclusive production process in the direct photon-photon
collision is still not being touched. As DJ production process has a clear
distinction from the single J/\psi inclusive processes in the final states,
experimental study on it would be helpful to clarify the validity of
color-singlet model.
