Abstract: A synoptic renew of the discoveries and studies of the Chinese Mesozoic birds is provided in this paper 40Ar/ 39Ar dating of several bird-bearing deposits the Jehol Group has established a geochronological framework for the study of the early avian radiation- Chinese Mesozoic birds had lasted for at least 11 Ma during about 131 Ma and 120 Ma（Barremian to Aplian) of the middle and late Early Cretaceous. In order to further evaluate the Change Of the avian diversity in the Jehol Biota, six new orders and families are erected based on known genera and species, which brings the total number of orders of Chinese Mesozoic birds to 15 and highlights a remarkable radiation ever since the first appearance of birds in the Late Jurassic. Chinese Early Cretaceous birds had experienced a significant differentiation in morphology, flight, diel and habitat. Further examination of the foot of Jeholornis suggests this bird might not have possessed a fully reversed hallux. However, the attachment of metatarsal I to the medial side of metatarsal II does not preclude trunk climbing, a pre-adaptation for well-developed perching life of early birds. Arboreality had proved to be a key adaptation in the origin and early evolution of bird flight, and the adaptation to lakeshore environment had played an equally important role in the origin of ornithurine birds and their near-modem flight skill. Many Chinese Early Cretaceous birds had preserved the direct evidence of their diet, showing that the most primitive birds were probably mainly insectivorous and that specialized herbivorous or carnivorous (e.g., piscivorous) dietary adaptation had appeared only in later advanced forms. The only known Early Cretaceous bird embryo fossil has shown that precocial birds had occurred prior to altricial birds in avian history, and the size of the embryo and other analysis indicate it probably had a short incubation period. Leg feathers probably have a wide range of distribution in early birds, further suggesting that leg feathers had played a key role in the beginning stage of the flight of birds. Finally, the Early Cretaceous avian radiation can be better understood against the background of their unique ecosystem. The advantage of birds in the competitions with other vertebrate groups such pterosaurs had probably not only resulted in the rapid differentiation and radiation of birds but also the worldwide spreading of pterosaurs and other vertebrates from East Asia in the Early Cretaceous.

摘要： 对中国中生代鸟类的发现和研究进行了简要的介绍。近年来生物地层学和年代地层学的工作表明，这些鸟类主要属于早白垩世的中晚期(13l～120 Ma)，延续了至少11Ma，但主要的辐射发生在125～120 Ma间。为便于分析早白垩世鸟类多样性的演变，本文依据已发表的化石，新建了6个目和科，从而将中国早白垩世鸟类目的总数提高到了15个，进一步揭示了鸟类出现以来第一次大规模的辐射事件。这一大的辐射还表现在鸟类在形态、飞行能力、个体大小、食性和生态习性等均出现了显著的分异。早期鸟类进化过程中首先经历了个体减小过程，其后