The early gonads of mammals contain primordial germ cells (PGCs) and somatic cell precursors that are essential for sex determination and gametogenesis. Although it is extensively documented in mice, the development of early gonads in non-rodents remains to be delineated. Because molecular differences between mouse and human gonadal cells have been reported, it warrants the study of the key markers and regulatory features that are conserved or divergent between non-rodent species and human. Here, we integrate single-cell transcriptome and chromatin accessibility analysis to identify regulatory signatures of PGCs and somatic cells in the early gonads of goats, pigs, macaques, and humans. We identify the evolutionarily conserved and species-specific events, including genes expression, signaling pathways, and cell-cell interactions. We also uncover potential cis-regulatory elements and key transcription factors in PGCs and somatic cells. Our datasets provide important resources for better understanding the evolutionary programs of PGCs and gonadal somatic cell development in mammals.