An atmospheric transmittance model for molecular oxygen absorption band near 762 nm is expressed by a polynomial including temperature and pressure. The polynomial coefficients are expressed as another power series of cosine of incident angle. Similarly, a mean atmospheric transmittance model is also given. Numerical tests indicate that under vast majority of circumstances the fitting errors (RMS) of the atmospheric transmittance model and those of the mean atmospheric transmittance model are less than 0.0001 and 0.0005, and their maximal errors are less than 0.0005 and 0.003, respectively. Both models were applied to the study on remote sounding of atmospheric pressure profile from space. In addition, a correction method is given for the interval error of atmospheric transmittance.