Gardiner and Theobald carried out the feasibility study for the proposed stadium. which is expected to cost £24m to build.
The cost consultants said a new stadium could generate around £3m in revenue for the council and create 400 jobs.
Councillors could consider the plans next month to build the new Cornwall Stadium at Langarth Farm, at Threemilestone.
If approved, the plans could also pave the way for a new 1,500-home housing estate nearby in an associated application.
The housing scheme would see the construction of shops, a restaurant, hotel, care home and the expansion of a park-and-ride service.
Truro City Football Club and the Cornish Pirates rugby team were both stakeholders in the study.
Cornwall Council said when it commissioned its first study into a stadium in 2010 that, if built, the stadium would help nurture regional sporting talent to compete on a national scale.