As business groups clamour for clarity on future trading arrangements and warn of financial services firms enacting contingency plans to maintain EU access, Forbes said the country had risen in its rankings from fifth last year to first.
The information specialist declared the UK was inside the top 25 nations in each of the metrics it judged, except for political risk.
An article for its magazine which launched the rankings said the country scored "particularly well" on technological readiness (fourth) and the size and education of its workforce (third).
It judged 153 countries on 15 factors including property rights, innovation, taxes and red tape.
The report pointed to the current dominance of the UK's financial services sector and investment by top US technology firms, including Apple, as major positives for the country.
It also cited low unemployment as a benefit.
Forbes' Kurt Badenhausen said: "Much uncertainty remains with the official exit from the EU scheduled for March 2019.
"Some UK companies are holding off on investments to see how Brexit effects trade relations, and growth is forecast to slow in 2018, but Britain's business climate remains attractive."
Sky News was seeking a response to the report from business groups which have, in addition to Brexit, cited low productivity and a lack of skills as obstacles for firms in the UK.
The rankings had New Zealand in second place, followed by the Netherlands, Sweden and Canada.
The US rose from 23rd to 12th place as President Trump moved to bolster the economy through a series of tax cuts.