Microwave-assisted pyrolysis of Dunaliella salina was carried out. The effect of different types (mixtures of activated carbon (AC) with CaO and AC with Fe2O3), different adding amounts (5, 10, 15, and 20%), and different mixing ratios (0:10, 3:7, 4:6, 5:5, 6:4, 7:3, and 10:0) of compound additives was evaluated, the results were compared with those of single additive and no additive groups. When the compound additive was a mixture of AC and CaO, the maximum weight loss rate (R-m) and average weight loss rate (R-v) of AC/CaO = 6:4 group at 20% addition were the largest, whereas the times corresponding to R-m (t(m)) and weight stabilization (t(s)) were the smallest. The total weight loss (M-t) of AC/CaO = 0:10 and 4:6 groups at 20% addition were the largest. When the compound additive was a mixture of AC and Fe2O3, the It, and R-m of AC/Fe2O3 = 5:5 group at 15% addition were the largest, while the t(s) and t(m) were the smallest; The AC/CaO = 6:4 group at 20% addition was the best based on the M-t of D. saline; the AC/Fe2O3 = 5:5 group at 15% addition was the best based on the R-m, R-v t(m), and t(s) of D. saline. (C) 2019 Elsevier Ltd. All rights reserved.