A rotary evaporator-assisted rapid cyclic acetal/ketal synthesis has been achieved. Different from the traditional use of Dean-stark for dehydration reactions which normally requires the long reaction time and large amount of organic solvent, the synthesis of cyclic acetal/ketal with different ring size is realized in a short time by using minimal amount of DMSO as solvent. This protocol is featured with high yield, fast reaction, easy operation, and wide substrate scope.