The study was conducted on two crops (spring - winter and summer) in 2010 in a vegetable growing area in Ha Hoi commune, Thuong Tin. Hanoi with three vegetables (cauliflower, coriander. dill) and Fastac 5EC and Daconil 75WP - two products that farmers use commonly on the above three vegetables. For each kind of vegetable, research three formulas: Control (no spraying); Formula 1 (Fastac 5EC (0.1 percent) and Daconil 75WP (0.2 percent"; Formula 2 (Fastac 5EC (0.2 percent) and Daconil 75WP (0.4 percent). Compare the economical efficiency of vegetables showed that pesticides contribute significantly to increased'crop yields, Without pesticides, real yield can decline from 10 - 50 percent. Vegetables of summer crop have a lower yield of that of winter, but a higher economic efficiency due to cost price is higher. However, vegetables of summer crop may leaving many at risk of toxic chemical residues in products because the interval between two sprays is rather short. Overall, with each crop Fastac 5EC ,and Daconil 75WP caused a decrease in number of species diversity of Collembola communities but increase the Collembola density compared to land without using pesticides. Use Fastac 5EC (0.1 percent) and Daconil 75WP (0.2 percent) is most appropriate, not only because of economy and efficiency and to reduce production costs but also they had no effect on micro - arthropods (Collembola) in the vegetable growing area of Thuong Tin, Hanoi.