Polymer blending is confirmed to be an effective way to produce cohesive peelable films for easy to open packaging. In this kind of films, upon peeling, a crack initiates at the interface of the blend components and propagates through the seal layer. This approach results in a very strong and reliable seal in which the two seal layers are strongly welded together while a low peel force is needed to open the package. In this work, blends of polyethylene (PE)/polybutene-1 (PB-1) with 5, 10 and 20 weight % of PB-1 were prepared through film casting as sealant films and were co-extruded with PE as support layer. Using selective solvent extraction technique, the morphological parameters of the blends films in the seal area such as the width (D) and the length of the elongated droplets (L), the interfacial distance, and the distance between two adjacent droplets were studied using scanning electron microscopy (SEM). A quantitative relationship between the morphological parameters and the seal/peel performances of the films (heat seal initiation temperature, heat seal temperature window, peel force and peel force consistency with time) was established.