The scales are estimated to have come from at least 20,000 to 30,000 slaughtered pangolins in Africa.
Nearly 12 tonnes of smuggled pangolin scales have been confiscated by Chinese officials - the country's largest-ever seizure of the endangered mammal's prized parts as it seeks to curb illegal trafficking.
The pangolin, whose brown scales have earned its nickname "scaly anteater", is the most hunted animal in the world, with one million estimated to have been plucked from Asian and African forests over the past decade.
The latest stockpile of scales was seized at a port in the southern city of Shenzhen this July and likely taken from between 20,000 to 30,000 slaughtered pangolins, state media reported on Wednesday.
The state-run China Daily newspaper said this marked the "largest volume of any single case found by border inspectors."
Police have arrested two suspects, surnamed Li and He, who used fake names to register their packages for import, state-run media added.
The suspects declared the packages empty, but were using charcoal-stuffed bags to cover nearly 250 sacks of pangolin scales.
On Li's mobile phone, police found photos of pangolin scales that were taken in an African country.
He denied taking the photos, claiming to have recently purchased the phone secondhand just prior to being taken in for questioning in September.
But one of the investigators noticed that a mole on Li's left foot matched one that appeared on a foot in one of the photos with the pangolin scales.
Investigators also found transactions totalling more than $758,000 between Li and He, who took the same flight to an unnamed African country.
Pangolins are under state protection in China, where some believe the animal's scales have medicinal qualities, despite no scientific evidence to support the claim. Eating pangolins is punishable by up to 10 years in prison.
The profit-margin is high for smugglers bringing pangolins into China or Vietnam from Africa, where it can be procured at low prices and then sold in Asia as a delicacy.
A ban on global pangolin trade went into effect at the start of this year.
In September, China's Wildlife Protection Association collaborated with conservation nonprofits on a video campaign starring Jackie Chan, in which the martial arts superstar urged viewers to say "no" to eating, using and buying pangolin products.