De Villota's team, Marussia F1, said her car hit the team support truck at the end of her first run at Duxford Airfield in Cambridgeshire. It was the first time the 32-year-old Spanish driver, who joined the team this season, tested the MR-01 car.
An ambulance spokesman said the injuries were life-threatening and De Villota was treated by paramedics at the scene before being transported to Addenbrookes Hospital.
Marussia confirmed De Villota's crash in a statement on its website.
"The accident happened at the end of her first installation run and involved an impact with the team's support truck," Marussia said. "Maria has been transferred to hospital. Once her medical condition has been assessed a further statement will be issued."
De Villota is the daughter of former F1 driver Emilio de Villota and joined Marussia as a test driver at the start of this season, becoming the sport's first full-time female driver since Italian Giovanna Amati with the Brabham team in 1992.
De Villota had previously tested for Renault and had racing experience in Spanish F3 and the Daytona 24-Hours.
The Russian-owned team started in Formula One as Virgin Racing in 2010 and rebranded as Marussia for the start of the current season. It has yet to pick up a point this year ahead of this weekend's British Grand Prix at Silverstone.
Its race drivers are Timo Glock of Germany and Charles Pic of France.