For photoacoustic wave production of an ellipsoid particle,we derive analytical formula for wave profile on symmetrical axis.It shows that either for a prolate ellipsoid particle or for an oblate ellipsoid particle,wave profile deviates from typical N wave for a sphere particle.Moreover,deviated N wave is found containing characteristic information about shape and size of the particle.It promises a method for investigating shape as well as size of ellipsoid particles by measuring pulsed photoacoustic wave.