But many lower pay grade civil servants in the CPS would get average annual pensions of £5,600 after 40 years' service - which they likened to "benefit money".
Gordon Thompson, 51, from Manchester, a senior CPS solicitor and convener for the First Division Association, which represents lawyers and senior civil servants, said: "This is my first strike and my first time marching for jobs in my life.
"We have made a choice in our careers - we chose to go into public service and work for less than in the private sector. One of the reasons was the pensions were generally better.
"Now they are taking that away.
"I'm disgusted, quite frankly, and disappointed at being short- changed by this Government."
Joy Lewis, 25, from Manchester, a paralegal for the CPS and member of the Public and Commercial Services union (PCS), said: "We say there is an alternative to public sector cuts by tackling the amount of tax avoidance and tax evasion. Address the tax loopholes.
"It should not be a race to the bottom. Private and public sector workers should get decent pensions.
"The Government is making the people who did not cause this crisis suffer. They should be looking at the bankers and their bonuses who caused this crisis.
"The Government is making a choice. We appreciate there is a problem with finance, but the Government is making a choice - it is choosing to take it from public sector workers, that is what it is choosing to do, from people who have small pensions."