There were 678 crimes against MPs reported between 2016 and 2020, police data shows.
The Parliamentary Liaison and Investigation Team, set up by the Metropolitan Police in 2016 following the death of Jo Cox, received 582 reports of malicious communications and handled 46 cases of harassment.
A total of nine cases were classified as relating to terrorism.
There were also seven reports of MPs receiving threats, and three cases of common assault over the period.
Separate police figures, released under the Freedom of Information Act, show a sharp rise in reports since 2018, with 34 incidents in December 2018 and 128 incidents in January 2019.
There were three threats to kill in the four months for which figures were provided.
In 2019, the Met said that crimes against MPs increased by 126% between 2017 and 2018, with a 90% rise in the first four months of 2019.
At the time, Met commissioner Dame Cressida Dick said: “The current context, in our policing time at least, is unprecedented.”
It comes as Conservative MP Sir David Amess died after being stabbed multiple times at a meeting with constituents.
A suspect has been arrested after the Tory veteran was stabbed several times during a “very distressing” incident at a constituency surgery in Essex.
The 69-year-old victim, who has been an MP since 1983, was fatally injured at Belfairs Methodist Church in Leigh-on-Sea in Essex midday on Friday.