“It won’t return sovereignty, it will put us at the mercy of Trump and the big US corporations,” Corbyn wrote.
Corbyn said a general election would be the best way of stopping it but he was open to other options.
Some MPs have mentioned the possibility of passing legislation to force the government to delay Brexit.
“I hope we can come to a good working arrangement and bring on board others across parliament who see the danger of a No Deal crash out,” wrote Corbyn.
The Labour leader has invited other opposition figures and pro-EU moderates from the ruling Conservatives to the talks in parliament on Tuesday.
Britain’s parliament is not due to resume until next week but anti-Brexit politicians have been discussing plans ever since Johnson came to power last month vowing to take Britain out of the EU on October 31 deal or no deal.
Johnson has said he is hoping for a deal with EU leaders.
The political impasse has raised the chances of a general election and politicians of all stripes are preparing.
The Brexit Party, which came first in European elections earlier this year and which advocates a no-deal Brexit, is presenting its candidates at a launch event on Tuesday.
Britain voted to leave the European Union in a 2016 referendum but has been forced to delay its exit twice after parliament opposed a deal struck with Brussels under Johnson’s predecessor Theresa May.
“Jeremy Corbyn’s Labour Party will do anything to try and block delivering the change that British people voted for in the referendum,” the Conservatives said in a statement.
“Only Boris Johnson and the Conservatives can provide the leadership the UK needs to deliver Brexit by 31 October, whatever the circumstances,” the statement said.
© Agence France-Presse