A new CCD photometry survey of the open cluster NGC7788 in U , B , V , R and I colors to magnitude V=20 is present . Extensive comparison of our photometry with other published dataset shows excellent agreement , indicating that CCD photometry is capable of producing a uniform set of measurements consistent with the photometric system defined primarily by the Landolt standard sequence . For this study we used the 113 stars considered to be cluster members by Becker on 1965 . Assuming R = 3,06 at ( B-V ) = 0.0 and the Zero Age Main Sequence of the Pleiades as reference locus with distance modulus 5.57 ( Walker 1985 ) , we have derived from the resulting color-magnitude diagrams new and more accurate estimates of the reddening and distance modulus of the cluster with turn out to be E ( B-V ) = 0,28 \pm 0 , 03 and ( m - M ) _ { o } = 11,9 \pm 0,24 respectively . With the parameters obtained and assuming solar compositions , the age of NGC7788 is 9 , 33 \times 10 ^ { 7 } yr , and the distance is 2398 parsec .