The RSCPA is hoping to trace a man apparently seen kicking his dog on a video online.
The footage, posted on the website YouTube, was purportedly shot in Knee Hill Park, Woolwich, in south-east London.
It shows a man in a white hooded top making a fawn-coloured dog run before kicking it twice.
The RSPCA described the footage as "extremely shocking" and asked members of the public to identify the culprit.
On several occasions the man pulls the dog into the air by its lead.
A spokesman for the charity said: "The footage is extremely shocking as it shows what appears to be a man deliberately kicking the dog with some considerable force.
"We are hoping that someone will recognise the person in the video and contact us with more information so we can find out who is responsible."