Merlin Attractions Operations Ltd, the company that runs Alton Towers, has said that it was responsible for health and safety failings over the Smiler Rollercoaster crash in June 2015.
Sixteen people were injured, five seriously, when two carriages collided on the rollercoaster.
An investigation into the accident found that there were not mechanical faults with the ride, but said that the people running the ride had caused it to crash.
A judge said that the company could have to pay "a very large fine" because of how serious the accident was.
After the crash, the company said that they had added more safety procedures.
Rollercoaster crashes like this are incredibly rare.
The International Association of Amusement Parks and Attractions say that the chance of being injured on an amusement park ride is one in 24 million.