The cross-capital route is set to start running trains from May 2022 and Southall station has been given a facelift ahead of the big date.
Network Rail has created a brighter, spacious station entrance with a new ticket hall built from glass and steel as well as a wider ticket gates.
It has also three new lifts and a new footbridge which provides step-free access to all four platforms at the station.
The station, which first opened in 1839, also has new signs with the bilingual information that was installed due to the large Punjabi community in the area.
Rail minister Chris Heaton-Harris said: “I’m pleased to see transformational upgrades completed at Southall station which improve accessibility and deliver better, more modern facilities for passengers.
“This will benefit the local community immediately and readies the station for when the Elizabeth line opens next year.”
New customer information screens and ticket machines have also been installed at the station.
Heidi Alexander, deputy mayor for transport, said: “I’m delighted that Southall is the latest station to benefit from a range of Elizabeth line upgrades including a more spacious entrance and step-free access.
“These improvements will make a big difference to passengers ahead of the opening of the line next year.”
The station building also now has a new forecourt and wider doors to reduce congestion at its entrance.
Howard Smith, TfL’s chief operating officer for the Elizabeth line, said: “The Elizabeth line is going to be transformational, and by opening the new ticket hall and lifts at Southall station there is now a modern entrance ready for customers to use for many years to come.
“It’s great to see the upgraded bilingual station signage alongside the wider refurbishments and I really hope the people of Southall are pleased with these new improvements which make the station much more accessible and inviting.”