Charges against the Popular Front for the Liberation of Palestine (PFLP) secretary-general on Sunday included involvement in a militant group and deadly attacks, weapons dealing, armed robbery and incitement to violence between 1995 and 2004.
The justice ministry had decided earlier that there was not enough evidence to charge Saadat over the 2001 killing of an Israeli cabinet minister, for which four of his comrades have been charged.
Khaleda Jarrar, a PFLP spokeswoman in the West Bank, said Saadat was innocent and "does not recognise the legitimacy of the court nor the charges they pressed against him".
Israeli state prosecutors charged four PFLP activists on May 12 with killing Rehavan Zeevi, the then Israeli tourism minister, in 2001. They are due to enter a plea on June 8.
The group said it shot Zeevi to retaliate for Israel's killing of its leader.
Saadat and the others were seized by Israeli troops in a March raid on a Jericho prison, where they had been kept since 2002 under a deal with the Palestinian Authority.
An Israeli army spokesman said Saadat could be jailed for life if convicted on all charges.
The PFLP opposes peace talks with Israel.
The group, which was at the forefront of plane hijackings in the 1960s and 1970s, is part of the umbrella Palestine Liberation Organisation.