The nine-year-old, who lives in a luxury five-star serviced apartment in the heart of Surfers Paradise, moved to the city from Moscow with her family three years ago.
Her mum Iuliia Perova said the mother-daughter duo started the Instagram account less than two years ago.
"It's hard to get people's attention on social media these days, that's why we thought we had to do something creative," Iuliia said.
"My background is in accounting, but I have lots of creative friends back in Moscow who give me inspiration.
"We started by creating our own outfits that were unique to attract followers - like a dress with crayons on it and a dress made of real popcorn with earrings and shoes as well.
"After a while we realised it was very time consuming to make outfits so we changed our focus to doing photoshoots with the clothes that we got sent to us … I have good equipment so we can do it all without booking a photographer and spending a lot of money.
"We're a family team."
Ms Perova said Katya built her following organically using relevant hashtags, posting quality photos once a day and interacting with other child models all over the world.
"I don't accept any payment for the posts that we do, but we get sent packages of clothes for her at least every week so I never have to buy clothes for her again," she said.
"I manage the account for her and I read through all the comments.
"Most of them are really lovely, people all over the world tell her how beautiful she is.
"But sometimes I have to delete inappropriate comments that have been said by really disgusting people.
"I only show her the positive things."
Katya said the social media platform had allowed her to start modelling without paying for an agent or professional photographers - but it was all just a bit of fun.
"My mum's friends always thought I was good looking and thin so they told me I should try modelling," she said.
"I started out doing photoshoots on the Instagram account for fun … I really liked wearing those beautiful dresses.
"I want to keep modelling and maybe get an agent when I'm older but right now it's just lots of fun and has given me a lot of confidence."