The invention provides branched type functionalized solution polymerized styrene-butadiene rubber and a preparation method thereof. A molecular chain of the prepared branched type functionalized solution polymerized styrene-butadiene rubber contains siloxy having good compatibility with white carbon black, a structural diagram is shown as (a), and the siloxane branched chain content is 0.1%-8% ofthe solution polymerized styrene-butadiene rubber by weight. The preparation method of the branched type functionalized solution polymerized styrene-butadiene rubber comprises the steps that organolithium is used as an initiator, a structural modifier is added, so that butadiene and styrene generate copolymerization, when the monomer conversion rate of the copolymerization is close to 100%, long-chain hydrosiloxane is then added, a beta-selective hydrosilylation catalyst and an addition agent are added for hydrosilylation, the reaction temperature is 60-120 DEG C, the reaction time is 30-120 minutes, after the reaction is completed, the branched type functionalized solution polymerized styrene-butadiene rubber is obtained through termination, coagulation and drying. The abrasion performance and wetting resistance of the solution polymerized styrene-butadiene rubber can be improved, and rolling resistance is lowered.