The present invention relates to a biaxially oriented polyolefin multilayer heat shrinkable film, which is a multilayer heat shrinkable film with at least three laminated layers, and has internal and external surface layers of a resin composition comprising 70-80wt% of an ethylene-norbornene copolymer having a glass-transition temperature (Tg) of 138°C and a norbornene content of 76wt%, and 20-30wt% of an ethylene-propylene random copolymer having a melting point (Tm) of 140°C; and a core layer comprising 54wt% of an ethylene-propylene random copolymer having Tm of 140°C, 8wt% of an ethylene-butylene random copolymer having Tm of 66°C, 20wt% of an ethylene-norbornene copolymer having Tg of 78°C and norbornene content of 65wt%, and 18wt% of a hydrogenated petroleum resin having softening point (Ts) of 140°C. The present invention provides a polyolefin heat shrinkable film and a method for preparing the same, the film has good temperature resistance, high transversal heat shrinkage rate, solves the problem that labels among bottles are easy to adhere between each other during hot filling drink or the problem about adhesion between labels and PE heat-shrinkable film in bundle-shrink pack of a group of bottles using the PE heat-shrinkable film, and is suitably used as label substrate material for contoured bottles.