The wild populations of Chinese sturgeon () have decreased dramatically since the 1970s because of environmental degradation, overfishing, and construction of the Gezhouba Dam in the Yangtze River. In 1989, was listed as a first-protected animal in China, also it has been on the IUCN Red List as a Critically Endangered species since 2009. The artificial propagation technology of was realized in 2012, and large-scale hatching of larvae is possible. However, the larval to juvenile stage is the main period of disease occurrence, especially when larvae start feeding and juveniles convert bait; there is often high mortality. This has seriously restricted the protection and utilization of the germplasm resources of . Thus, it is critical to understand the development of the immune system. The goals of this research were to understand the early developmental process and characteristics of the immune organs of by anatomical and histological methods. This provides morphological and histological data for the early development of the lymphoid organs of , and also accumulates basic data for the large-scale cultivation of fry. The healthy larvae and juveniles of F₂ with 1-300 dph were regarded as appropriate species for this test. The occurrence of immune organs (head kidney, thymus, and spleen) was observed and recorded by means of continuous paraffin section and microscopic observation. The results showed that the primordia of immune organs from appeared in the order of the head kidney (3 dph), thymus (7 dph), and spleen (9 dph), and small lymphocytes appeared in the order of the thymus (12 dph), head kidney (15 dph), and spleen (33 dph). At 15 dph, lymphocyte bridges were observed between the head kidney and thymus. At 180 dph, Hassall's corpuscles were observed in the thymus, and Melanocyte or Melano-macrophage centers (MMCs) were found in the head kidney, thymus, and spleen. In conclusion, the immune organs of have the characteristics of early primordial differentiation, a slow developmental rate, and a long developmental cycle. Because the structure of the immune system is not fully developed from larval to juveniles, it is suggested that disease prevention and vaccine development should be strengthened in the early cultivation process.