The present invention discloses a modified polypropylene special resin, which is characterized by mainly comprising the following components: chlorinated polyolefin, a butadiene rubber, a vinyl monomer, and a terpene resin, wherein a weight ratio is 1:0-0.5:0.1-2:0.003-0.15. According to the modified polypropylene special resin, a long chain of the chlorinated polyolefin is adopted as a skeleton, and a tertiary carbon position or a secondary carbon position on the chlorinated polyolefin is grafted with the vinyl monomer and/or the butadiene rubber or/and the terpene resin. The modified polypropylene special resin of the present invention has good adhesion and good boiling water resistance, and a preparation method for the resin is simple, and is easy to industrialize.