The incident took place at a premises on Neilston Road around 9.30pm on Thursday, April 29.
An unidentified man entered the shop and threatened staff with a knife before running away with the till screen.
He was chased by a staff member down Neilston Road towards the junction with Calside and Causeyside Street, when he then threatened the shop employee again with his knife.
The suspect then ran off in the direction of Calside.
The man is described as white with a local accent, and is about 5ft 7in in height.
He was wearing a dark Adidas tracksuit top with red stripes on the shoulder and sleeves, black jogging bottoms and white Lacoste trainers.
He also had a white face mask and black gloves on.
Detective Constable Robert Young of Paisley CID said: “Nobody was injured but this was a frightening experience for the staff involved.
“Extensive enquiries are ongoing to identify the man responsible, including reviewing CCTV from the area.
“Anyone who believed they may have information which could help to identify the man or who was in the area at the time of the robbery is urged to contact police as soon as they can.
“I would also encourage anyone who may have been driving in the area and recording via a dash-cam device to check your systems for relevant footage.”
Anyone with information is asked to contact police on 101, quoting incident 3545 of April 29, or alternatively you can call Crimestoppers anonymously on 0800 555 111.