A laser transmitter and receiver are respectively arranged on the low-orbit space station and its companion satellite. Both the 935-nm short-wave infrared band vapor detection laser beam pulse pair and 765-nm near-infrared band laser beam pulse pair (located in the oxygen absorption A-band) are transmitted and received simultaneously. One detection wavelength of the 935-nm band pulse pair strongly absorbs water vapor and other reference wavelength exhibites relatively weak absorption of water vapor; one wavelength of the 765-nm band is strongly absorbed by oxygen and other wavelength is weakly absorbed by oxygen. An Abel transformation relation exists between the two-wavelength differential optical depth of the entire optical connection and differential extinction coefficient at the tangent point of the connection. Based on Abel integral transformation, the numerical calculation is performed using the ideal gas law and the atmospheric quasi-static equation, taken the atmospheric model as the initial condition. The 765-nm wavelength pair is used to invert the atmospheric pressure and temperature, whereas 935-nm wavelength pair is used to invert the atmospheric water vapor density. Simulation results and error distribution of the water vapor profile distribution are obtained. Results show that laser occultation has the potential to detect the level of water vapor in the troposphere-stratosphere (5--14 km).