Three men - Ken Cresswell, 57, and John Shaw, 61, from Rotherham, and Chris Huxtable, 34, from Swansea - have been missing since 23 February.
The body found on Wednesday has not been identified, but contractors have paused work so specialists can enter the site to recover the remains.
Thames Valley Police said the families of the three men have been informed.
The body of Michael Collings, 53, from Brotton, Teesside, was previously recovered from the site.
The building was due for demolition when it partially collapsed. The remaining section was brought down using explosives last month.
Searches were halted in May when contractors reached a 50m (164ft) exclusion zone, beyond which it was considered too dangerous to continue.
The families of the three missing men had opposed plans to use explosives for the demolition.
A body has been located at the former Didcot Power Station six months after the collapse of its boiler house.