Lisa Arnold, 52, previously admitted to taking the money at the force’s Winfrith headquarters.
The force said its handling of the case demonstrated that it would “pursue and deal with those who seek to undermine the trust that is placed in us by the public.”
Concerns were first raised in June 2020 following reports that an exhibit bag containing cash had been tampered with.
Further incidents were also noted, involving exhibit bags containing cash that had not been counted yet for evidential reasons. Audits of a property store also revealed further tampered items.
An investigation was undertaken by the force’s Counter Corruption Unit to identify the individual involved, including financial checks and the inspection of access records to the relevant store areas.
Ms Arnold was identified as a suspect and arrested in March 2022, leading to her immediate suspension from work.
A subsequent search of her home address led to £15,000 in cash being seized.
She formally resigned from Dorset Police in May 2022.
Ms Arnold was sentenced to two years in prison at Bournemouth Crown Court on Wednesday, having previously pleaded guilty to the offence on 7 December 2022 at Weymouth Magistrates’ Court.
Following the sentencing, Dorset Police Deputy Chief Constable Sam de Reya said: “I hope that this investigation demonstrates that we will robustly investigate suspected wrongdoing by members of our organisation and undertake swift action.
“Our officers and members of staff are expected to execute their duties with integrity. On this occasion a staff member has fallen short of those standards and been found guilty of a criminal offence.
“We will pursue and deal with those who seek to undermine the trust that is placed in us by the public and let down colleagues and the police service.”