Provided is an analysis method and device of influence of direct drive fans on subsynchronous resonance of a power transmission system. The method comprises the steps of conducting equivalence on a series compensation power transmission system to obtain an equivalent parameters; building a simulation system according to single direct drive fan and a power transmission system equivalent model, obtaining a direct drive fan impedance characteristic of the direct drive fan in a subsynchronous frequency band through frequency scanning, and obtaining a double-fed fan impedance characteristic of a double-fed fan in the subsynchronous frequency band; performing calculating to obtain a mixed fan impedance characteristic after multiple double-fed fans and multiple direct drive fans are connected in parallel and a single fan impedance characteristic after the multiple double-fed fans are connected in parallel according to the direct drive fan impedance characteristic, the double-fed fan impedance characteristic and matching of the double-fed fans and the direct drive fans; judging subsynchronous resonance influence condition of the direct drive fans to the double-fed fan series compensation power transmission system under the matching by comparing the mixed fan impedance characteristic with single fan impedance characteristic. According to the analysis method and device of influence of the direct drive fans on the subsynchronous resonance of the power transmission system, subsynchronous resonance influence of the direct drive fans can be effectively analyzed.