Bellway Homes is running the residential side of the development, while Simons delivers an Asda store, 11-screen cinema complex and five restaurants at the derelict former Arla Foods dairy site in Victoria Road.
The 60-week scheme is worth nearly £26m to Simons and includes extensive highway alterations.
The scheme is being constructed beneath the main flight path of RAF Northolt where the planes will be around just 500ft from the level of the site when taking off or landing.
Works are being carried out by Aviva on the adjoining retail site, so a great deal of collaboration will be required in the area.
Daemon Sheehan, construction director of Citygrove said: “We are extremely pleased to have appointed Simons to deliver our retail and leisure development at South Ruislip. The scheme has many constraints and challenges and Simons have shown an excellent understanding and planning of the works.
“The scheme includes many sustainable elements and will achieve a BREEAM Very Good rating. We look forward to working with Simons and building our relationship with them.“
Tom Robinson, chief executive of Simons said works would begin in the next few weeks.