The latest figures for company turnover in the Bank of Scotland Business Monitor are the best results for almost seven years.
Almost half of the firms surveyed (46 per cent) said they had seen their turnover rise in the three months to the end of May, while 36 per cent said their turnover had stayed the same and 18 per cent experienced a decrease.
Bank of Scotland chief economist Donald MacRae said: "The surge in economic activity identified in summer 2013 has been maintained into summer this year.
"Expectations are at their highest level since mid-2007, suggesting the recovery will continue throughout 2014. Further increases in investment by firms would enhance the recovery."
The survey of 408 businesses also showed the recovery in export activity had been maintained over the period of March to May this year.
More than one-quarter (27 per cent) of firms surveyed said exports activity had increased in this period, while 60 per cent said it was static and 13 per cent reported a fall.
Almost half (47 per cent) of the businesses questioned expect their total volume of business to increase in the six months between May and November, while 46 per cent expect to see turnover grow and 31 per cent believe exports will rise over this period.
Finance Secretary John Swinney said: "These encouraging figures show continued improvement in the Scottish economy, with the Business Monitor showing the economy is now performing at levels not seen since the recession and business expectations for the next six months remaining at levels last seen in 2007.
"There are grounds for optimism, with a higher balance of firms than at any point in almost seven years reporting an increase in turnover.
"These figures add to the recent positive news on employment, inward investment, tourism and manufacturing - all of which show the Scottish economy performing well as we emerge from the recession."