An XL Bully dog killed two sheep and injured another five while being walked in Wild Park, a court heard.
Steven Baker, 29, has been charged with owning an XL Bully type and being in charge of a dog worrying livestock on 22 February this year.
The sheep were all Herdwick sheep and were on agricultural land next to Wild Park when they were attacked.
Baker, of Grove Hill, Brighton, appeared at Brighton Magistrates Court on 16 July. He denied both charges, and will go on trial next year.
The dog is currently being held in kennels pending the end of legal proceedings.
Councillor Theresa Fowler, lead member for animal welfare, said: “Our livestock perform an incredibly important role in helping to manage our parks and green spaces and it is absolutely vital dog owners make every effort to control their pets when near grazing sheep, or indeed when walking their animals anywhere there may be sheep or cows nearby.
“The sheep we use to graze our sites in the city are arranged through our grazier, who works out of a local farm. They oversee the welfare of the sheep, arrange treatment for any who are sick or injured, or in the worse-case scenario, sensitively remove sheep who have sadly died or been killed.
“We also have a team of volunteers who undertake daily checks while the sheep are on site.
“When one of our animals is injured or killed by a dog, it is an incredibly upsetting and distressing time for everyone involved.
“We are not able to comment on an on-going legal case, but we would politely remind residents who are walking dogs near sheep in our parks, on near livestock on the South Downs, to keep them on a lead and under control at all times.”