According to the analytic expressions for the spin-lattice coupling coefficients G11and G44in cubic symmetry for d8ions derived from a uniform method based on the relations between the coefficientsG11and the stress dependence of zero-field splitting, the coefficients G11and G44for Ni2+ions on KMgF3and KZnF3crystals have been calculated by using two adjustable parameters (the average covalency) reduction factorNand ligand dipolep) obtained from electron paramagnetic resonance and optical absorption spectra. The absolute values of the calculated results are in agreement with the data obtained from spin-lattice relaxation experiments, and the signs of these coefficients are predicted to be positive from the theoretical calculation.