Following a week of growing controversy over its Southwest One joint venture with IBM, local police and Taunton Deane BC, the council said it had made£27m in savings over the last three years against a target of£22.6m.
Public services union Unison and local MP Ian Liddell-Grainger have both criticised the back-office shared services deal of being overly secretive and demanded investigations by the Audit Commission.
The council said its most significant savings were in the areas of adult social care, supporting people, and waste.
Resources and finance leader Sam Crabb (Lib Dem), said the cash saved by the council could be reinvested in improving frontline services for the community.
David Huxtable (Con), chair of the council's audit and resources scrutiny committee, said that exceeding the government's efficiency saving targets by 20% was a "considerable achievement" and that the county and its districts had even greater ambitions for future savings.
"I hope that Somerset County Council will continue to improve efficiency savings to help reach the County's aim of£55m of savings in the next three years," Cllr Huxtable said.
Under a framework deal, another 33 local authorities could sign up for back office servics provided through Southwest One.
Somerset CC alone believes it will save£1.7m a year from its involvement in the 10-year joint venture.