Abstract: In order to calculate the optical transmittance of water vapor in the strong absorption bands fleetly,the application of the correlated k-distribution(CkD) method in the calculation of the optical transmittance of water vapor in the strong absorption bands was studied, and the corresponding program was designed and developed.The technical details in the CkD method, including the chose of integration grid points, the interpolation of the absorption coefficients in the inhomogeneous atmosphere was also discussed.Tested on the six standard atmospheric models, good results were obtained.The results indicate that the CkD algorithm is accurate and efficient in the calculation of atmospheric transmittance of water vapor in the strong absorption bands, and the CkD practical in actual application.