Beibeilong sinensis was discovered by Zhang Fengchen, a farmer from the Xixia Basin of Henan in China, between December 1992 and early 1993. It was described in 2017 by thirteen paleontologists: Pu Hanyong, Darla K. Zelenitsky, Lü Junchang, Philip J. Currie, Kenneth Carpenter, Xu Li, Eva B. Koppelhus, Jia Songhai, Xiao Le, Chuang Huali, Li Tianran, Martin Kundrát, and Shen Caizhi.
The specimen was discovered by Zhang Fengchen, and he, with some other farmers, excavated it in late 1992 or early 1993. The visible specimen consisted of four fossilized eggs. In mid-1993 the specimen was illegally sold to an American company called The Stone Company, run by Florence and Charlie Magovern from Boulder, Colorado. Charlie was inspecting the eggs, and thought he saw some bones in a chisel gouge. He cleaned away some of the rock, and confirmed the presence of bones. Three of the paper's authors (Philip Currie, Kenneth Carpenter, and Karen Zelenitsky) traveled to The Stone Company to study the specimen. During this time, a National Geographic photographer, Louis Psihoyos, came to document the unearthed skeleton. The skeleton was from then on referred to as Baby Louie in honour of Louis. The full skeleton was unearthed, and the entire specimen was acquired by the Indianapolis Children's Museum in 2001. The specimen was finally returned to the Henan Geological Museum in China in 2013. In 2015, five of the paper's authors (Philip Currie, Eva Koppelhus, Pu Hanyong, Lü Junchang, and Jia Songhai) traveled to the excavation site with Zhang Fengchen, and found fossilized eggs identical to those found in the specimen. The specimen is thought to be a small section from what would have been large ring-shaped nest.
Beibeilong is an oviraptorosaur theropod from the caenagnathidae family, a group of very large oviraptorosaurs also known as megaoviraptors. It is considered to be more basal than other caenagnathids, except for Microvenator. During its early analysis in the late 90s, it was originally thought to be a therizinosaur, but further comparisons with other caenagnathid skeletons and eggs (the eggs referred to as Macroelongatoolithus) confirmed the family as caenagnathidae.
The holotype consists of a partial skeleton, called Baby Louie, and six to eight eggs. Baby Louie is spread across two eggs, and is missing its tail; the tail could have been eaten by scavengers or is simply hidden beneath the rest of the skeleton. There is also an unidentified limb bone sticking out of one of the eggs. Baby Louie's skull is crushed, and parts of it, the neck, forelimbs, and abdominal bones are all strewn together in the abdominal region of the skeleton. Boring insects appear to have damaged parts of some of the bones. Estimations of the length of other Macroelongatoolithus eggs of similar size as those in the nest of Baby Louie suggest the weight of Beibeilong may be between 1,000 and 1,100 kg.
The eggs of the nest are generally arranged in a ring facing outwards. Baby Louie is thought to be an embryo, judging by its bone structure, positioning, and size. Its head is tucked into its chest, in a position like modern crocodiles in their own eggs. Its curled size is also small enough to fit inside its surrounding eggs. Because its curled size is just over half the length of the eggs, Baby Louie appears to have been forcefully removed from its egg before becoming fully developed.
Like other caenagnathids, Beibeilong is carnivorous, as evidenced by its jaw and skull similarity to other caenagnathidae specimens.
Beibeilong comes from Pinyin. "Beibei" translates to "baby", as Beibeilong was fossilized as a baby. "Long" translates to "dragon", as is the common replacement for "saurus" in Chinese dinosaurs. Sinensis comes from Latin, referring to the fact that the dinosaur is from China.