Wavelet analysis is a popular subject in science research. The notion of univariate orthog- -onal wavelet packs is generalized. First, the notion of biorthogonal nonseparable trivariate wavelet packs is proposed and a procedure for constructing them is presented. Next, the biorthogonality pro- -perty of trivariate wavelet packs is investigated, and three biorthogonality formulas of wavelet packs are established. Moreover, it is shown how to gain new Riesz bases of space from these wavelet packs.