An integrated positioning mechanism of hydrant shell plate, of which the hydrant has an upper shell plate, a lower shell plate and an integrated positioning mechanism; the upper shell plate has a pedestal, an upper base plate, screw holes and a mating side; the lower shell plate is assembled beneath the upper base plate of the upper shell plate, and provided with two threading seats and an assembly side; moreover, the integrated positioning mechanism comprises a locking portion with a flange and a concave coupled together, as well as two bolts, thus enabling limited assembly of the upper and lower shell plates; with this unique design, the present invention allows two bolts and the locking portion to position the hydrant more stably and firmly by a three-point fixation way, thus improving substantially the quality of the hydrant with innovative applicability.