The invention belongs to the biotechnical field, and specifically relates to a biopesticide and a preparation method of the biopesticide. The insecticidal efficacy of the biopesticides is greatly improved by adding an extract of a Jacaranda mimosifolia branch and a peony root extract into a pesticide. The extract of the Jacaranda mimosifolia branch and the peony root extract have no toxic effect to human and livestock, so that when the biopesticide provided by the invention is used, people do not need to worry about adverse effect of the biopesticide on the human body. By further adding saccharomycetes after 6-7 days of microculture, not only are the microorganism species enriched, but also the organic components in the pesticide are increased to promote growth of plants. By using beauveria bassiana and green muscardine fungi in the biopesticide, injurious insects in forests, nursery gardens, lawns and fields and the like can be effectively prevented and treated. The biopesticide provided by the invention has the characteristics of efficiency, environment friendliness, no secondary toxicity, no residue and no pollution, maintained ecological balance and no public nuisance, is an important guarantee to realize green and ecological agriculture and green enterprises, and has a wide prospect.