Production and Suppression of Charmonium in Nuclear Collisions

$J\mathrm{/}\psi$ production cross section considering the contributions of both color-singlet and color-octet $c\bar{c}$ channels is calculated. The result is used to study the suppression of $J\mathrm{/}\psi$ in nuclear collisions. With absorption cross sections for $(c\bar{c}{)}_8$ ${\sigma }_{abs}^8\simeq 11mb$ and $(c\bar{c}{)}_1$ ${\sigma }_{abs}^1\simeq 0mb$ the p-A and A-B data except for Pb-Pb can be explained. Possible explanations of additional suppression in Pb-Pb are discussed.