The invention discloses an efficient environmentally friendly ecological insecticide for a garden. The insecticide is prepared from, by weight, 40-50 parts of plant dry powder, 3-6 parts of inorganic bases, 14-18 parts of binder, 15-19 parts of insecticide synergist, 7-9 parts of surfactant, 2-4 parts of realgar, 4-6 parts of penetrant, 8-10 parts of stabilizer, 8-14 parts of propylene glycol and 120-160 parts of water. The efficient environmentally friendly ecological insecticide for the garden is harmless to plants, the insecticidal effect is good, the insecticide is unlikely to dry and volatilize, the efficacy time is long, and the control efficiency of garden plant pests such as red spider, aphid, whitefly, scale insect, pseudaulacaspis pentagona, Aromia bungii, Spodoptera litura, tortrix, loopworm, Arge pagana and the like is good; a number of plant insecticidal components which are nontoxic and harmless to environment are used in the raw materials; meanwhile, according to the preparation method provided, the production cost is low, the process is concise, and the preparation method has high practical value and good application prospects.