"I was a little surprised because Manchester United don't have that custom of sacking managers," Ancelotti said.
"In another club it would be completely normal, but after so many years with Sir Alex [Ferguson] it is a little surprising."
Moyes was sacked on Tuesday, after less than ten months as Ferguson's successor, with United enduring a poor season.
"I feel for David Moyes, but in general this is the life of a coach," Ancelotti told a press conference ahead of Real's UEFA Champions League semi-final, first leg against Bayern Munich on Wednesday.
"At times things don't go well and you are sacked. I'm sure David Moyes will look for and find another job."
Legendary former Manchester United and Real Madrid players
Click this Classic Players link to read about the superb careers of former George Bestm Paul Breitner, Bobby Charlton, Didi, Alfredo Di Stefano, Gheorghe Hagi, Raymond Kopa, Michael Laudrup, Ferenc Puskas, Ronaldo, Hugo Sanchez, Peter Schmeichel, Ricardo Zamora & Zinedine Zidane.