The unnamed traveller was stopped by customs officers as he sought to slip out of Hong Kong and into the border city of Shenzhen, China Customs said in a statement on Tuesday.
"Upon inspection, customs officers discovered that the pockets of the trousers the passenger was wearing were packed with six canvas drawstring bags and sealed with tape," the statement said.
"Once opened, each bag was found to contain living snakes in all kinds of shapes, sizes and colours," it added.
The statement said officers seized 104 of the scaly reptiles, including milk snakes and corn snakes, many of which were non-native species.
An accompanying video showed two border agents peering into transparent plastic bags filled with squirming red, pink and white snakes.
China is one of the world's biggest animal trafficking hubs, but authorities have cracked down on the illicit trade in recent years.
The country's biosecurity and disease control laws forbid people from bringing in non-native species without permission.
"Those who break the rules will be... held liable in accordance with the law," the customs authority said, without specifying the man's punishment.