The diversity of small shelly fossils (SSF) demonstrates that multicellular organisms underwent large-scale radiation at the beginning of the Cambrian, which is highlighted by the coexistence of various metazoans and the occurrence of their embryo fossils. However, little is known about early Cambrian eukaryotic multicellular algae, the primary producers that replaced oxygenic cyanobacteria and played a crucial ecological role in matter cycling and energy dynamics in marine ecosystems. In this study, hundreds of microscopic three-dimensionally preserved multicellular agglomerate fossils were obtained from the early Cambrian Kuanchuanpu Formation (535 Ma) in southern Shaanxi, South China, which consisted of several tightly-packed multicellular clusters encapsulated within a thin organic membrane. Synchrotron tomography analysis further revealed that the cells of the whole agglomerate, although partitioned into different subunits by a gelatinous membrane, were distinctly differentiated into an outer conical cell layer and an inner spherical-cell layer, thus suggesting of a cortex-medulla-like differentiation. These characteristics resemble those of multicellular algae (e.g. Wengania, Gremiphyca, and Thallophyca) from the Ediacaran Weng’an biota (South China) in morphology, size, and internal cell structure. Furthermore, a potential asexual life cycle for these membranous algae was proposed based on their morphological and structural characteristics. Our findings support an evolutionary continuity of the multicellular algae from the Ediacaran to the early Cambrian Period.