The woman, in her fifties, was uninjured in the attack which took place at around 8pm on Tuesday, October 30.
Police were called to Moorland Road in the Hyde Park area of Leeds to the victim, who was coming out of the Woodhouse Moor park onto Moorland Road when the incident happened.
Neither the victim or her dog were struck by the items, but she was distressed by the incident and the guide dog attempted to run off.
Officers are looking for three to four youths, as well as two women who helped the victim after the attack.
West Yorkshire Police said in a statement: "Shortly before 8pm last night (30/10), police were contacted by a blind woman who reported having fireworks thrown towards her by youths in Moorland Road, Hyde Park.
"The victim, who is aged in her fifties, was with her guide dog and was coming out of the Woodhouse Moor park onto Moorland Road when the incident happened.
"Neither she nor her dog were struck by the items and both were uninjured, but she was left upset and distressed. The dog was startled and had tried to run off.
"She told officers it sounded like three to four youths were involved and that they had been about 20 metres away on the path that runs parallel to Moorland Road, near to the junction with St John’s Avenue.
"Two women came to her aid and helped her to safety. Officers are keen to trace those women as potential witnesses to the incident.
"Officers are checking CCTV in the area and would like to hear from anyone who witnessed the incident or who has any information that could assist the investigation.
"Anyone with information is asked to contact the Leeds North West Neighbourhood Policing Team via 101 quoting crime reference 13180544785 or call the independent charity Crimestoppers anonymously via 101."
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