The boy, aged two, sustained serious but non-life-threatening injuries when set upon by the dingo about 7pm on Friday at Dales Campground in Karijini National Park.
He has since been released from Tom Price Hospital, WA Country Health Service said on Sunday.
Parks and Wildlife Rangers spent Saturday trying to find and trap the wild dog.
"The safety of visitors is our number one priority," it said in a statement.
"Due to the aggressive behaviour of the dingo and the fact that it has remained at the campground following the incident, rangers are preparing to humanely destroy the animal as soon as a safe opportunity presents."
While interactions with humans can be common in some WA national parks, attacks are rare.
The department wasn't aware of another attack in that part of Karijini, a rugged national park half the size of Sydney.
"Signage and information at Dales Campground warns visitors that dingoes may be present and provides dingo safety advice," it said.
The local government in the coastal town of Karratha last month warned visitors dingoes were frequently seen in Karijini and other popular national parks, and the animals may raid rubbish bags and take food from picnic tables.
"While searching for food or water dingoes may harass and intimidate people," the City of Karratha said.
20°C