"I intend to resign after Prime minister's questions on Wednesday", Hammond told the BBC's Andrew Marr Show.
Hammond is expected to be sacked when Boris Johnson, the favorite to become Britain's next prime minister, takes office.
Johnson is believed to require a "loyalty pledge" for all his future cabinet members to accept a possible No Deal Brexit on October 31.
"I am sure I am not going to be sacked because I am going to resign before we get to that point," Hammond said, Euronews reported.
"Assuming that Boris Johnson becomes prime minister, I understand that his conditions for serving in his government would include accepting a no-deal (EU) exit on the 31st of October. That is not something I could ever sign up to."
Hammond has vocally opposed a No Deal Brexit scenario in separate occasions. He warned last week that the UK would "lose control" of many key sectors of its economy, including the crucial trade link at the French port of Calais, if the country leaves the EU without a deal.