Pompey have been training at the Wellington Sports Ground for 11 years, but the stricken club can no longer afford to rent the facility.
The League One strugglers have been in serious financial trouble after going into administration twice since 2010.
Portsmouth are also looking at other sites in the city in a bid to ease the burden on their home ground.
A statement from the club read: "Portsmouth Football Club will stop using the training facilities at the Wellington Sports Ground in Eastleigh at the end of the month.
"Going forward, the club will use Fratton Park and will also look to use other facilities in the city."