The invention discloses a pasty biological pesticide composite and a preparation method thereof. The biological pesticide composite comprises pesticide components and an auxiliary component. The pesticide components are biological prevention funguses. The biological pesticide composite is characterized in that the auxiliary material is starch which accounts for 5%-10% of the total weight of the composite. The biological prevention funguses refer to trichoderma, penicillium, chaetomium, cylindrocarpon, fusarium, Beauveria bassiana and / or metarhiziumanisopliae; a copper ion inhibitor, the addition amount of which is 0.001%-0.05% of the total weight of the composite, is added in the composite; in addition, hydrochloric acid, the addition amount of which is suitable for adjusting the pH value to 3.0-4.0, is also added in the composite. The composite and biological pesticides prepared by using the method have the greatest advantages of stable product quality, long preservation time (18 months at normal temperature with high activity and 3 years in refrigeration condition); in addition, the invention has fastidious formula and advanced process, does not generate any wastewater, waste gas or waste residues, and is beneficial to environmental protection.