The proposals, designed by Bennetts Associates, are for a glass and steel structure that will let in natural light, creating a bright, airy and welcoming environment for passengers.
A new forecourt is expected to make it much easier for passengers to get in and out of the station, and avoid congestion at the entrance.
A range of other improvements will be made to the station, including a new footbridge, three new lifts, platform extensions, new lighting, customer information screens, station signage, help points and CCTV.
The work will be carried out by Network Rail and is due to begin this summer lasting around two years.
From the end of 2017, the station will be run by Transport for London as part of London’s integrated transport network.
Crossrail has also been working with Ealing Council and Network Rail to help develop plans for improvements around both the new and existing station buildings, which can be implemented when the new station building has opened.
Councillor Julian Bell, leader of Ealing Council, said: “We have worked closely with Crossrail to ensure that the design of the station in Southall is innovative as well as being practical.
"The new design makes it as easy as possible for passengers to use, while also making a significant improvement to the town centre in line with the regeneration work that is already well under way in the area.”
When TfL-run Crossrail fully opens in 2019, up to ten services an hour in each direction will serve Southall station, allowing passengers to travel right through central London without having to change trains.
Passengers will be able to get to Bond Street in 17 minutes and the journey to Canary Wharf will take 31 minutes.
Crossrail surface director Matthew White said: “The Crossrail improvements will transform the station and deliver a larger building that will serve local people for many decades to come.”
By improving transport links, Crossrail is said to already be unlocking development opportunities in west London, encouraging investment and supporting local jobs and businesses.
Almost half of planning applications (44%) within a kilometre of the five stations in the London Borough of Ealing cited the new railway as a justification for the development proceeding, such as Southall Gas Works.
The 83-hectare brownfield site has outline planning permission for a development of 3,750 homes and 525,000sq-ft of commercial and community space and a primary school.