Abstract: For microwave humidity and temperature sounder (MWHTS) on board FY-3C satellite, an one-dimensional variational system is built to inverse the atmospheric temperature and humidity profiles over ocean in clear sky. By analyzing the various factors affecting the accuracy of inversion, the system parameters can be determined. A statistical regression method is adapt in pixel by pixel correction procedure to correct the bias of brightness temperatures between the observed values and those simulated by Radiative Transfer Model for TOVS (RTTOV). This paper inverses the clear atmospheric temperature and hu-midity profiles over the north-west Pacific using the corrected measurements and the results validates that of the European Centre for Medium Range Weather Forecasts (ECMWF) reanalysis data. The results show that the maximum root mean square errors are 1.48 K and 22.69%, respectively. The contrast results of the retrievals and the background profiles show that the accuracy of forecast profiles can be improved effectively by inversion using FY-3C/MWHTS.