A method to assemble muti-chip CCD devices together for a long focal plane assembly was proposed to meet the need of a space wider format camera for large field of view. By using a long array Time Delay Integration CCD(TDICCD) mosaic apparatus, 17 TDICCD devices were stitched onto the focal plan board with an interleaving assembly method according to the accuracy requirements, and fixed by plugs, then an extra long focal plane with a length of 600 mm, pixels of 69 000 was obtained. The experiments on the completed focal plane assembly were performed by a temperature cycling test, a vacuum thermal test and a vibration test, and the results show that structure design and material selection of the focal plan assembly meet the mechanical and thermal requirements. The accuracy measurment result of focal plane shows that the stitching error is less than 3 μm. The extra long focal plane was applied to a remote sensing camera, and the seamless wider format image was captured. These results testify that the 600 mm long focal plane assembly meets the application needs of wide format remote sensing cameras.