To elucidate the impacts of culture temperature on nutrient removal efficiency of Pyropia-processing wastewater (PPW) and microalgal biomass production, Chlorella sp. C2 was employed and cultivated in raw PPW under different temperatures. Results showed that, after incubating for 7 days, higher biomass (0.50 g/L) and total lipids (21.84 %) were attained at 35 °C. The maximal chemical oxygen demand (COD), phycobiliprotein, total nitrogen and total phosphorus removal rates were observed at 30–35 °C and separately reached 62.41 %, 92.61 %, 92.19 % and 98.33 %. Interestingly, COD removal efficiencies of Chlorella cells, cultivated for 3, 5 and 7 days at 30–35 °C, 15–25 °C and 10 °C respectively, could reach >75 % with assistance from 60–80 mg/L chitosan. Meanwhile, the clarification efficiency of chitosan on algal cells reached >95 %. It suggests that Chlorella strain cultured at altered temperatures could efficiently remove PPW nutrients assisted by moderate chitosan, simultaneously achieving the rapid harvest of microalgae.