The Studio Ghibli film grossed $27.7m (£21.8m), according to Maoyan, China's largest movie ticketing app.
Spirited Away was officially released in 2001, but only now, 18 years later, has it been released in China.
However, many Chinese viewers grew up with the film, having watched DVDs or pirated downloads.
Toy Story 4 made $13.2m on its opening weekend, said consultancy firm Artisan Gateway.
The Japanese film by famed director Hayao Miyazaki tells the story of a young girl who is transported into a fantasy world after entering an abandoned theme park with her parents.
The movie gained a cult following after it was released and still remains Studio Ghibli's highest grossing movie of all time.
It also became the first non-English language animated film to win an Academy Award.
Image copyright2001 STUDIO GHIBLI - NDDTMImage caption10-year-old Chihiro is the film's main protagonist
Spirited Away has also already outperformed My Neighbour Totoro which grossed $27.3m for its full run, state media outlet CGTN reports.
Totoro was the first Ghibli film to ever debut in theatres in China, which has a strict quota on the number of foreign films it shows.
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