The crash happened on the A41 near Albrighton at 4.50pm and exacerbated delays to and from the nearby RAF Cosford Air Show.
A Skoda Rapid, VW Golf, Citroen C5 and Audi Q3 were involved, and a female passenger who was in the Golf is still being treated in hospital.
She is said to be in a stable condition with injuries that are not thought to be life-threatening. The driver of the Golf and a back-seat passenger were also treated for minor injuries.
The A41 was shut for almost five hours while emergency services dealt with the crash, which happened one mile away from RAF Cosford where around 60,000 people were at the annual air show.
Three ambulances and a paramedic officer were sent to the scene and found four people being cared for by passers-by. The injured woman was taken to New Cross Hospital in Wolverhampton.
Drivers leaving the air base were forced to turn left towards the M54 roundabout as there was no access on the A41 towards Wolverhampton.
Police are investigating and have appealed for witnesses to come forward.
Anyone with information is asked to contact West Mercia Police on 101, quoting reference 574s of June 10.