Abstract: Chemical reduction of exfoliated graphite oxide has been considered as one attractive potential approach for large-scale production of grapheme nanosheets,and its exfoliation step has a major influence on the quality of product.In this paper,ultrasonic cleaner and ultrasonic disintegrator were used to exfoliate graphite oxide into grapheme oxide nanosheets.Their frequency and mode effect on this exfoliation was studied.The result shows that exfoliation efficiency of graphite oxide increases with increasing ultrasonic frequency.Ultrasonic cleaner causes less serious damage on grapheme oxide nanosheets than ultrasonic disintegrator does,and it can be used to produce graphene oxide nanosheets with lager lateral size.