The small shelly fossils appeared along with a large number of phosphatized embryo fossils. These embryos provide a unique window for paleontology, and its information including developmental biology has brought new hope for revealing the secret of Cambrian explosion. As more and more new specimens were recovered, the embryonic developmental sequence of Olivooides as well as the relationship between Olivooides and Punctatus, is widely built. However, the developmental stages of these embryos are between embryos of late blastula stage and hatch animals. The intermediate stages (cleavage and blastula stages) are seldom reported. Based on several exceptionally-preserved three-dimensional embryo fossils and the slice of embryo fossils, we suggest a nearly complete developmental sequence being from a fertilized egg to cleavage, blastula and gastrula stage, then toward larvae. In comparison with Weng′an Biota in Guizhou province and their modern equivalents, it is found that the embryos from the Neoproterozoic Doushantuo Formation are similar to our specimens. In this paper, the developmental data facilitate a thorough integration of palaeontology into evolutionary developmental biology on understanding the biological evolution.