The invention discloses two-component silicone sealant for a solar module resisting damp, heat and ageing and a preparation method thereof. The sealant consists of a component A and a component B, wherein the component A adopts polydimethylsiloxane as the major material; and the component B comprises dispersion mediums, fillers, cross linking agent, coupling agent and catalyst; the component A comprises the following components in parts by weight: 100 parts of a, omega-dihydroxy polydimethylsiloxane with viscosity of 5000-50000cps, 3 to 20 parts of plasticizer and 50 to 150 parts of fillers; the component B comprises the following components in parts by weight: 100 parts of dispersion mediums, 10 to 45 parts of fillers, 20 to 50 parts of cross linking agent, 5 to 40 parts of silane coupling agent and 0.5 to 2 parts of catalyst; and the ratio of the component A to the component B in parts by weight is 100: (10-20). The sealant has the advantages of fast deep curing, wide adhesion, high strength of normal temperature and excellent resistance to damp, heat and ageing; after ageing for 1000 hours under the double-85 condition, the strength retention rate can be up above 80%; and the sealant is suitable for machine gluing, can largely improve module productivity, and adapts to the requirements of solar module mass production.