The 60ha Wakefield park, scattered with art by the likes of Henry Moore and Barbara Hepworth, said outdoor and indoor exhibitions proved big hits.
Meanwhile, a study by DC Research revealed the park is worth more than £5m to the local economy.
"These statistics underline its importance as a major international centre of artistic excellence," said executive director Peter Murray.
Last April was the busiest month ever with 50,000 visitors, while the June number was up 167 per cent on 2010.
The rise was credited to an exhibition by Spanish artist Jaume Plensa. Some 99 per cent of visitors said they would visit again.