Conte guided Chelsea to an unlikely Premier League title last season as his tactics fired the Blues back to the top of the table.
Chelsea will compete in the Champions League in the upcoming season after spending a campaign watching from the sidelines.
Ancelotti, a former Chelsea manager and current Bayern Munich boss, has warned Conte that he needs to add several top players to his roster.
‘Conte will be forced to change something, as he won the Premier League using practically the same players all the time,’ he said.
‘In the Champions League, he’ll need to buy a lot and buy well.’
Ancelotti spent two years at Stamford Bridge winning the league title and an FA Cup in his first season.
But, like so many Chelsea managers before him, he was let go and the latest man in the hotseat is Conte.
Chelsea pre-season fixtures
Arsenal – Sat July 22
Bayern Munich – Tues July 25
Inter Milan – Sat July 29
The Italian did indeed use virtually the same eleven for much of the title-winning season and rotated between the same 14 players.
Conte has already admitted he needs to bring in players this summer, but is reportedly frustrated with Chelsea’s lack of progress in the market.
Deals for Juventus full-back Alex Sandro and Monaco midfielder Tiemoue Bakayoko have so far failed to materialise.
Antonio Rudiger is now a Chelsea player (Picture: Chelsea)
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Top target Romelu Lukaku is set to snub Chelsea and join rivals Manchester United, but the Blues did announce a new signing on Sunday.
Roma defender Antonio Rudiger has joined the club in a £34million move and the centre-back is tipped to go straight into Conte’s side once the season gets underway.
Rudiger follows former Manchester City stopper Willy Caballero and Exeter City teenager Ethan Ampadu to the club this summer.