He told Tories in Aberavon on Friday night the two senior Labour figures posed the "greatest risk to economic growth... the country has ever seen".
UK and Welsh Labour both had a "hard left", "anti-business" agenda that "won't create jobs", Mr Davies said.
A Welsh Labour spokesman dismissed the speech as "a laughable rant".
Mr Davies accused Labour of abandoning "mainstream politics" by electing Mr Corbyn, but he also suggested that people in Wales have been "guinea pigs for Corbynism all along".
For 16 years, he claimed, Labour had made Wales a "failed test bed for the hard left".
Mr Jones met Mr Corbyn for the first time on Wednesday, with a spokesman describing the occasion as "positive".
A Welsh Labour spokesman said: "This is a laughable rant even by Andrew RT Davies's lowly standards.
"It is simply a cheap rip-off of the 'New Labour New Danger' attack ads from 1997 and we all remember how that worked out for the Conservatives.
"If the Tories want to spend the Assembly election campaign banging on about Marx and communism then good luck to them, it just makes them look ridiculous."
Jeremy Corbyn and Carwyn Jones are the "two most dangerous men for Wales' future", Welsh Conservative leader Andrew RT Davies has warned.