The incident occurred at approximately 3.30pm, prompting emergency services to rush to the scene.
Ambulance crews and police attended to the injured at the annual Christian music and worship event, which is being held at Wilton Park near Steyning from August 28 to August 30.
At least six people were taken to hospital for treatment, with the 41-year-old man, from Eastbourne, died at the scene, Sussex Police has confirmed.
The organisers said the event had been “paused” following a “serious incident”, with no further programming taking place today.
They said: “First and foremost, our thoughts and prayers are with those who have been directly impacted by the incident.
“We understand this will be deeply disappointing for the thousands who have joined us at the festival.”
The festival, a non-profit gathering that has run since 2009 and drawn up to 40,000 attendees at its peak, has been placed on full lockdown, with all performances halted as paramedics and specialist response teams work to treat those affected.
The festival, a non-profit gathering that has run since 2009, draws up to 40,000 attendees
Witnesses at the scene described a chaotic aftermath, with one festival-goer reporting “lots of ambulances and police” and a helicopter touching down close to the worship tent.
“From what I’ve gathered the worship tent sign has blown over and landed on a few people,” he told The Sun.
The festival-goer added he had been inside the worship tent shortly before the incident and had stepped out to head towards the main stage.
Alarm spread further when the festival’s live stream on GOD TV was abruptly cut.