Abstract: 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.