The utility model provides a syringe is used in insulating oil sample of special dosage of syringe and electric power system. The special dosage of syringe, including graduated flask centre gripping subassembly, location baffle and screw rod, two grip blocks that graduated flask centre gripping subassembly used including the cooperation are equipped with the convex groove that a cooperation was used respectively on two grip blocks, this two convex marge becomes to be used for the centre gripping hole of centre gripping syringe graduated flask, the location is equipped with two unthreaded holes on the baffle, and the one end of two screw rods is slided respectively and is passed corresponding unthreaded hole after -fixing on same grip block, two screw rods respectively with the syringe graduated flask is parallel to each other, and is fixed through the nut between two screw rods and the location baffle. Pacify respectively the inboard in two convex grooves has the arc slipmat, all is equipped with the arch on the lateral wall of two arc slipmat, is equipped with respectively on the inside wall in two convex grooves the positioning groove that uses of protruding cooperation. This scheme can not only improve the sampling precision of syringe, can also improve the efficiency that operating personnel passes through the syringe sample.