The incident happened around 8.45pm last night when Neil Gibson, of Willowford Farm, near Camptown, confronted a man and woman who he found looking around the yard.
The couple took off after being questioned as to what they were doing snooping around, but Mr Gibson says they also threatened him with a hammer.
He caught part of the confrontation on camera which he later shared on Facebook, urging people to be aware and to keep an eye out for the car or couple, which he believes made off south on the A68 towards Carter Bar.
The film shows the couple engaging with Mr Gibson before speeding off along the farm track, stopping to open the gate and heading off on the main road.
Mr Gibson wrote: “Keep a look out for this bloke and car. Just caught him breaking into a caravan up at farm, when I cornered him he came at me with an axe-type hammer.
“He’s got a blonde girl with him and a King Charles cavalier dog. He’s armed with an axe, so be careful.
“He headed south on A68.”
The social media post showing the videos and pictures has been shared more than 760 times and police are appealing for information to help trace the couple.
A Police Scotland spokesperson said: “Officers were called to Willowford Farm in Jedburgh around 8.45pm last night, following reports of a break-in.
“After threatening a man with a weapon, two suspects, a man and a woman, left the scene in a blue Renault Clio.
“Anyone with any information on the incident is asked to contact 101 quoting incident number 3894 of Tuesday, August 22.”