The kinetic of hydrolysis for cinnamylidene aniline derivatives has been investigated by ultraviolet spectrophotometry in 20% (v/v) dioxane - $H_2O$ at $25^{circ}C$. A rate equation which can be applied over wide pH range was obtained. The substituent effects on cinnamylidene aniline derivatives were studied and the hydrolysis was facilitated by electron attracting group. Final products of the hydrolysis were cinnamaldehyde and aniline. From the rate equation, substituent effect and final products, the hydrolysis of cinnamylidene aniline derivatives was initiated by the neutral molecule of $H_2O$ which does not dissociate at below pH 9.0${sim}$12.0, but proceeded by the hydrogen ion at above pH 5.0${sim}$9.0.