The invention relates to the field of thin film materials and device manufacturing, in particular to a film forming liquid injection device for centrifugal film preparation equipment. The device comprises a rotating drum, a film forming base body, a needle head, a device for moving the needle head in the direction of a rotating axis of the drum, a needle injection angle adjusting device, a needlehead stretching and retracting device and a film forming liquid pressurization assembly, the film forming base body is arranged on the inner surface of the rotating drum, a sliding rod I is arranged on the device for moving the needle head in the direction of the rotating axis of the drum, the sliding rod I is in sliding fit with the device for moving the needle head in the direction of the rotating axis of the drum, one end of the needle injection angle adjusting device is arranged at the tail end of the sliding rod I, the needle head stretching and retracting device is arranged at the otherend of the needle head injection angle adjusting device, a needle head is arranged on the needle head stretching and retracting device, and the needle head is connected with the film forming liquid pressurization assembly through a pipeline. The film forming liquid injection device is mainly used for injecting the film forming liquid of different substances into the surface of the rotating base body in the form of a liquid column so as to realize accurate control and preparation of a thin film structure.