In this paper，the limitation is pointed out about honeycomb fiberboard in existence. A novel structure of quasi-rhombic sandwich core is developed for honeycomb fiberboard. Forming way of the sandwich core is analyzed and its basic dimension parameters are calculated. The qualitative analysis and the tested results indicate that the performances of cushion and foldable of quasi-rhombic honeycomb fiberboard are better than that of hexagonal honeycomb fiberboard，so as to used for cushion packaging material and to made foldable honeycomb paper box.