NOVELTY - Nicotine-containing plant source synergistic compound insecticidal composition, comprises nicotine and turpentine oil as the main component, which is formed by adding with an auxiliary agent. The composition is in the form of emulsion, preferably microemulsion. The microemulsion comprises (in wt.%): nicotine (1-50), turpentine oil (5-40), emulsifying agent (5-15), synergistic agent (0-20), penetrating agent (5-40), and the remainder is organic solvent with respect to 100 wt.% of composition.    USE - The nicotine-containing plant source insecticidal composition is useful for preventing small green leafhopper, aphid of yellow apple, cabbage aphid on fruit trees, vegetable and flower, small long pipe aphid, medlar aphids, and aphids of mulberry, tea, peach, pear, cotton, tobacco, hemp and other economic crops.    ADVANTAGE - The composition does not contain any chemical pesticide, has low-toxicity, excellent synergisitic effect and wide application spectrum, and is environmentally-friendly.    DETAILED DESCRIPTION - Nicotine-containing plant source synergistic compound insecticidal composition, comprises nicotine and turpentine oil as the main component, which is formed by adding with an auxiliary agent. The composition is in the form of emulsion, preferably microemulsion. The microemulsion comprises (in wt.%): (a) nicotine (1-50), turpentine oil (5-40), emulsifying agent (5-15), synergistic agent (0-20), penetrating agent (5-40), and the remainder is organic solvent with respect to 100 wt.% of composition, (b) nicotine, turpentine oil, organic solvent (0-20), surfactant (5-15), synergistic agent (0-20), antifreezing agent (4-10), and remainder is water with respect to 100 wt.% of the composition, (c) nicotine, turpentine oil, organic solvent (0-20), surfactant (5-20), synergistic agent (0-20), antifreezing agent (4-10), thickening agent (0.2-1), and remainder water with respect to total weight of the components (100%). An INDEPENDENT CLAIM is included for method of preparing the composition, which involves which involves mixing nicotine, turpentine oil, emulsifier, organic solvent, penetrating agent, and synergistic agent, uniformly stirring the mixture in the reaction kettle, checking the quality of the product, or mixing nicotine, turpentine oil, organic solvent, surfactant, active agent, synergistic agent, anti-freezing agent, thickening agent and water, subjecting the mixture to emulsification to obtain emulsifying dispersion.