The invention discloses a modified polyurethane waterproof seal glue, comprising the following components by weight parts: 65 parts of polyether glycol, 35 parts of polybutadiene polyurethanes, 60 parts of dicyclopentadiene petroleum resin, 2, 5 parts of castoroil or glycerol used as a chain extender, 0.5 part of organic silicon flatting agent used as a defoamer, 0.5 part of fluorocarbon flattingagent used as a flatting agent, 1 part of PVC plasticizer used as a plasticizer, 0.2 part of manganese naphthenate used as a catalyst and 35 parts of calcium carbonate, calcium hydroxide and silica used as a filler. The manufacture method comprises the following steps: (1) decompressing and dehydrating the polyether glycol; (2) adding the polybutadiene polyurethanes to carry out a reaction; (3) drying the dicyclopentadiene petroleum resin; (4) adding the chain extender, the defoamer, the flatting agent, the plasticizer and the catalyst to stir for the first time; and (5) adding the filler to stir for the section time. The invention has good mechanical property and low production cost.