Four kinds of silicon nitride composites with tri-laminate structure were prepared by stacking tapes with aligned ${eta}-Si_3N_4$ whisker seeds. The composites were fabricated using a modified tape casting method for enhanced alignment of the whisker seeds. The relative densities of all four samples reached 99% at room temperature. The three-point flexural strengths of the samples according to the stacking sequences were measured at both room temperature and 1723 K. The high temperature strength of sample WWW was $457{pm}14$ MPa. The fracture of sample WWW occurred mainly along the grain boundary. The room temperature strengths of samples OOO, OWO, WOW, and WWW were $430{pm}32$ MPa, $470{pm}19$ MPa, $700{pm}14$MPa, and $940{pm}14$ MPa, respectively.