The utility model discloses an upside-down hydraulic pressure synchronous jacking device of a liquefied natural gas storage tank. An oil pump master station is connected with an oil outlet primary oil circuit distributor through an oil outlet main oil circuit, at least three primary oil circuit outlets are arranged in the oil outlet primary oil circuit distributor, each primary oil circuit outlet is connected with a jacking branch with an electro-hydraulic proportional flow valve, and each single jacking branch is connected with an oil outlet secondary oil circuit distributor. Each oil outlet secondary oil circuit distributor is provided with three secondary oil circuit outlets, and the branches connected with the corresponding secondary oil circuit outlets are respectively connected with a primary shunt flow-combining valve. Two outlets of each primary shunt flow-combining valve are respectively provided with a jack, and two adjacent jacks in the four jacks connected with a first primary shunt flow-combining valve and a second primary shunt flow-combing valve in each jacking branch are respectively connected with an oil inlet of the first secondary shunt flow-combing valve through an oil return branch. The upside-down hydraulic pressure synchronous jacking device improves construction efficiency.