Enquiries into the footage are under way after the incident in Hoe Street, Walthamstow, was shared on social media.
In the clip, a woman is seen shouting: “Shame on you… shame on you despicable people.
“God created Adam and Eve, not Adam and Steve.”
Responding to the abuse, the Pride participant, who was draped in a rainbow flag, said: “We still love you, you will not shame me.”
“Abusing someone because of their sexual orientation or gender identity is a hate crime”
Waltham Forest Police
Waltham Forest Police said: “We are aware of footage circulating on social media of abuse directed at those taking part in Waltham Forest Pride event and enquiries are under way.
“Abusing someone because of their sexual orientation or gender identity is a hate crime.
“If you have been verbally or physically abused, harassed or attacked in any way by someone because you are or they think you are LGBT+ please report these crimes to police or through a third party agency.”
Walthamstow MP Stella Creasy condemned the abuse in the clip and said she was “gutted” to see “such hatred.”
“Gutted to see this and clear such hatred isn’t acceptable anywhere, let alone in our home town,” she wrote online.
Baroness Warsi insisted the woman be held accountable for her actions.
She said: “This woman needs to be found, the facts established and if a criminal act has been committed, she must be charged.”
Last month, two women were allegedly subjected to a homophobic attack on a London night bus.
Melania Geymonat and her partner Chris were left bloodied by a group of teenagers after it is said they refused to kiss on demand.
Four teenagers aged 15 to 17 have been charged with an aggravated hate crime and will appear in court on August 21.