A frame synchronization method for image data, wherein the method comprises the following steps performed by an image signal processing unit: receiving a frame synchronization instruction sent by a first image collection apparatus of a terminal; separately sending the frame synchronization instruction to a second image collection apparatus and a third image collection apparatus of the terminal, so that the second image collection apparatus, the third image collection apparatus, and the first image collection apparatus synchronously output frame image data; receiving the frame image data synchronously sent by the first image collection apparatus, the second image collection apparatus, and the third image collection apparatus; and processing the received frame image data, to generate a displayable image, characterized in wherein before said receiving a frame synchronization instruction sent by a first image collection apparatus of the terminal, the method further comprises: receiving a first control signal sent by a control chip of the terminal, wherein the first control signal comprises address information of synchronization registers of the second image collection apparatus and the third image collection apparatus; and said separately sending the frame synchronization instruction to a second image collection apparatus and a third image collection apparatus of the terminal specifically comprises: separately sending the frame synchronization instruction to the synchronization registers of the second image collection apparatus and the third image collection apparatus based on the address information of the synchronization registers. receiving a frame synchronization instruction sent by a first image collection apparatus of a terminal; separately sending the frame synchronization instruction to a second image collection apparatus and a third image collection apparatus of the terminal, so that the second image collection apparatus, the third image collection apparatus, and the first image collection apparatus synchronously output frame image data; receiving the frame image data synchronously sent by the first image collection apparatus, the second image collection apparatus, and the third image collection apparatus; and processing the received frame image data, to generate a displayable image, characterized in wherein before said receiving a frame synchronization instruction sent by a first image collection apparatus of the terminal, the method further comprises: receiving a first control signal sent by a control chip of the terminal, wherein the first control signal comprises address information of synchronization registers of the second image collection apparatus and the third image collection apparatus; and said separately sending the frame synchronization instruction to a second image collection apparatus and a third image collection apparatus of the terminal specifically comprises: separately sending the frame synchronization instruction to the synchronization registers of the second image collection apparatus and the third image collection apparatus based on the address information of the synchronization registers. receiving a first control signal sent by a control chip of the terminal, wherein the first control signal comprises address information of synchronization registers of the second image collection apparatus and the third image collection apparatus; and said separately sending the frame synchronization instruction to a second image collection apparatus and a third image collection apparatus of the terminal specifically comprises: separately sending the frame synchronization instruction to the synchronization registers of the second image collection apparatus and the third image collection apparatus based on the address information of the synchronization registers.