Benzaldehyde glycol acetal was synthesized from benzaldehyde and ethylene glycol using aluminum dihydrogen tripolyphosphate / loaded sulfur diatomite catalyst. The effect of molar ratio of alcohol to aldehyde, catalyst amount and reaction time on yield was studied by single-factor experiments. Box-behnken design and response surface analysis were used to obtain the optimization technical conditions of the synthesis of benzaldehyde glycol acetal. The results show that the three main influencing factors are in the order as follows: aldehyde alcohol mole ratio > reaction time > the quantity of catalyst. Variance analysis of multiple regression model show that the optimal technical condition is: temperature 115℃, molar ratio of benzaldehyde to glycol is 1: 2.6, reaction time1.23h, the quantity of 1%, water-carrying agent of cyclohexane 10mL. Under these conditions, the yield of benzaldehyde glycol acetal is above 88.1%. After catalyst repeated use five times, the yield of benzaldehyde glycol acetal still is 86.1%.