Polyhydroxyalkanoates (PHA) are biopolymers which can be accumulated by prokaryotic microorganism as intracellular reserve carbon source in the absence of nutrients resource. PHA, being the potential substitute of the conventional plastics due to their similar physical and chemical properties as those petroleum-based traditional plastic as well as good degradability and biocompatibility, would save fossil resources and hence became a hotspot in the biosynthesis of degradable materials research field. Numerous studies in recent years proved that the activated sludge with mixed microbial culture can significantly reduce the costs of PHA synthesis, and further beneficial to the industrialization of PHA synthesis and wastes reclamation. This paper systematically summarized the research progress of activated sludge-based PHA synthesis in the enrichment and accumulation phase, illustrated the PHA enrichment bacteria selection process (from AN/AE mode to aerobic dynamic discharge mode) and accumulation phase (from fed-batch to continuous feeding mode), and emphasized the feeding mode optimization on the PHA enrichment and accumulation phase. Meanwhile, new ideas of research on PHA synthesis and the dynamic model of PHA synthesis were summarized. The paper also proposed some suggestions for the future research focus on the PHA production based on recent research progress on PHA synthesis with mix culture method.