Do American f2b immigrants need a marriage certificate for cancellation?

No need. The parties need to prepare household registration books, identity cards, stamped letters of introduction issued by the village (neighborhood) Committee where the household registration is located, etc. Before, immigrants could cancel their ID cards, while American f2b immigrants did not need a marriage certificate for cancellation. According to the U.S. immigration law, once you apply to cancel the U.S. green card, you will revert to your previous non-U.S. resident status.