Morgan Sindall, Mansell and Osborne are helping the council with the BuildSurrey site which is due to go live in February.
Council chiefs insist that work with main contractors will be awarded on the basis of quality as well as price.
The BuildSurrey site will also act as an apprenticeship matching service – bringing businesses offering places together with potential candidates.
Surrey County Council deputy leader Peter Martin said: “In the current climate, we must do everything we can to support the local economy and our aim is to ensure 60% of the county council’s spending is with local businesses.
“Just like on eBay, local firms will be able to bid, with the big difference being that on our website the firm offering the best combination of price and quality will win the deal.
“Big business is always going to need help wiring a building or installing window frames and doors and there can be no better way for the council to help local firms thrive than by putting money in their bank accounts.”
Local firms will have to register on the site and be vetted to ensure they provide a good service and hold any necessary qualifications before they can bid for work.