The present invention relates to use of pyrroloquinoline quinone (PQQ), a derivative and/or a salt thereof of formula (I) in the preparation of a drug for treating and/or preventing primary Sjogren' s syndrome, secondary Sjogren' s syndrome as well as dry mouth, dry eye and multiple system damages accompanied by the involvement of other exocrine glands and other organs outside the glands caused by Sjogren' s syndrome. In formula (I), R1, R2 and R3 being same or different, each independently representing lower alkyl, lower alkenyl, lower alkynyl, aralkyl, alkaryl, phenyl, a hydrogen atom, sodium atom or a potassium atom; and PQQ or pharmaceutical combinations of PQQ combined with active vitamin D, NAC, resveratrol, epigallocatechin gallate, curcumin, anthocyanin, vitamin E, vitamin C, or vitamin D and the like. The drug and the pharmaceutical combinations can treat Sjogren' s syndrome and associated diseases which are derivative of Sjogren' s syndrome. The present invention can remove excess oxygen radicals in the body, inhibit NF-kB activation caused by oxidative stress, and inhibit autoimmunity, thereby reducing the inflammatory response of Sjogren' s syndrome.