The small walled burial ground in Carmunnock Road, which links to Cathcart Old Parish Church, is thought to be more than 1500 years old.
Only the tower and gable end remain of a church on the site, but archaeologist Peta Glew has now found evidence suggesting ruins that could be hundreds of years older remain beneath the ground.
This could take the ruins to about 100AD, just at the end of the Iron Age in Scotland.
Ms Glew shared her findings with the community and locals who formed Cathcart Heritage Group to further explore the history of their area.
Ms Glew, 30, from Langside, made the discoveries while working for her Masters qualification at Glasgow University.
She said: "I am flattered that what was originally a small fieldwork project to give university students extra practice with field techniques has prompted the community and inspired the interest it has."
Working with a group of 25 students using hi-tech methods, Ms Glew found iron objects, stone walls and structures that create a picture of what is under the ground.
She found documents that link the church and 12 others to Paisley Abbey, which prove it was in existence in some form in the 12th Century.
But evidence of other Iron Age burial grounds in the wider area suggest it could be much older.
Ms Glew said she thought there had probably been five churches on the site since the 1160s until the late 1920s when the former Cathcart Old Parish Church, which dates to the 1830s, was demolished, leaving only the tower and gable standing.
Teri MacFarlane, secretary of Cathcart Heritage Group, said she was, "gobsmacked" when she heard the burial ground could be that old.
She said: "We want to let people know there is a heritage group and we want to bring people in with an interest of the history and the area.
"It is the kind of area where you turn the corner and there is another historical point."
In a separate venture, Simshill And Old Cathcart Community Council received £15,000 from Glasgow City Council's community council fund to light up the Gothic-style tower, which dates to the 1830s. Secretary Patricia Cockburn said the plans had been in place for a couple of years, but technical difficulties had delayed the process.
She said the lights would be turned on in May and added: "It will let people see we want to make the area as nice as possible and there is a lot of history in and around Cathcart and Old Cathcart."
The ancient burial ground is the resting place of the Polmadie Martyrs, whose tomb dates to the 17th century.
They were shot by soldiers in 1685 for supporting the Scottish Presbyterian Covenanters' cause.
More recently the grandparents of the Hollywood actor Stewart Granger, whose grandfather was a hero in the charge of the Light Brigade in the Crimean War, are also buried in the cemetery.