Emergency services were called to Zoe Colleran Hair and Beauty on Croxteth Hall Lane at 01:45 BST following reports that a white Ford Transit truck had crashed into the shop.
The front of the building collapsed and adjoining properties have been damaged.
Merseyside Fire Service said it was investigating the cause of the fire.
Three fire engines attended the blaze, which spread from the shop to the first-floor flat above it and also damaged four adjoining bedsits.
The road outside the shop has been closed while investigations continue, Merseyside Police said.
A Liverpool hair salon has been severely damaged by a fire which broke out after a suspected stolen pick-up truck crashed into the building.