Abstract: In this paper, toxic effects of nine pesticides to nymphs and eggs of Neoseiulus cucumeris (Oudemans) were tested using four methods. The 24-h LC₅₀ values of 25% thiamthoxam WG and 0.5% matrine and nicotine AS to nymphs and eggs of N. cucumeris were 3128.49 mg·L^-1 and 1802.67 mg·L^-1, 26.37 mg·L^-1 and 27.01 mg·L^-1, respectively. The corrected mortalities by the two pesticides were all less than 10% tested by methods of spraying and secondary poisoning, indicating that the two pesticides had little effect on nymphs and eggs of N. cucumeris. The 24-h LC₅₀ values of 0.3% azadirachtin emulsion to nymphs and eggs were 7.43 mg·L^-1 and 8.70 mg·L^-1, and the corrected mortality was at the range of 5.17%-36.21% and 3.95%-28.5%, respectively, by methods of spraying and secondary poisoning, indicating that 0.3% azadirachtin emulsion had low toxicity to the nymphs and eggs. Also, 80% zineb WP, 80% mancozeb M-45 WP, 50% mancozeb WP and 50% carbendazim and thiram WP had no toxicity to nymphs and eggs, as indicated by the low corrected mortalities (less than 5%) of these four pesticides. 86.2% cuprous oxide WP and 77% copper hydroxide WP had no toxicity to eggs, as indicated by the low corrected mortalities (less than 5%) of these two pesticides, but the corrected mortalities to nymphs were 16.81% and 9.32%, respectively, indicating that they had low toxicity to nymphs.