The 41-year-old man rode his horse into the Clermont Showground about 3.30pm on Sunday before charging at the gates where the woman was standing, Queensland Police said.
The 62-year-old NSW woman fell to the ground suffering bruising and abrasions and was taken to Clermont Hospital in a stable condition.
The man was arrested after he tried to flee from police into bushland. He is being questioned by police at Clermont station.
About 350 people gathered at Clermont Showground on Sunday as part of an anti-Adani convoy spearheaded by former Greens leader Bob Brown and which has travelled from Tasmania to Queensland.
Mr Brown described Sunday’s incident as a “senseless attack”.
The convoy protesting against the proposed Carmichael mine outraged Clermont locals, with the town’s three pubs refusing to serve those opposed to the mine.
The group is expected to leave the central Queensland town on Monday and will travel through Rockhampton and Yepoon as it makes its way to Parliament House in Canberra.
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