Disclosed are a system device for preparing an alkylate oil using a sulfuric acid catalyst and a manufacturing method thereof. The system device comprises a reactor unit (100), a catalyst and hydrocarbon circulation unit (200), a separator unit (300), an isobutane circulation unit (500) and a fractionator unit (400). The reactor unit (100) is connected and in communication with the catalyst and hydrocarbon circulation unit (200) and the separator unit (300) via channels respectively. The catalyst and hydrocarbon circulation unit (200) is connected and in communication with the separator unit (300) via channels. The separator unit (300) is connected and in communication with the isobutane circulation unit (500) and the fractionator unit (400) via channels respectively. The catalyst and hydrocarbon circulation unit (200), the separator unit (300), the isobutane circulation unit (500) and the fractionator unit (400) are connected and in communication with the reactor unit (100) via channels respectively. The reactor unit (100) comprises at least a high gravity reactor. Due to the adopted high gravity reactor capable of highly reinforcing the mixing of materials under high viscosity, the system device can operate at a low temperature of −5° C. and prepare the alkylate oil having an octane number of 97-100 at an alkane/alkene ratio of 2-100.