First-principles calculations and Monte Carlo methods were carried out to study the adsorption properties and photoelectric properties of TiCl4 gas molecules in armchair carbon nanotubes. The results reveal that: armchair carbon nanotubes have a strong physical adsorption effect on TiCl4 gas molecules. The absolute values of the adsorption energy of the studied configurations are more than 0.9 eV, which makes armchair carbon nanotubes ideal filling carriers for TiCl4 gas molecules. As the diameter of carbon nanotubes increases, the adsorption energy first increases and then decreases. The increase of temperature is not conducive to the adsorption of TiCl4 gas molecules, and the increase of gas fugacity is conducive to the adsorption. The temperature should be maintained near the boiling point of TiCl4 and the pressure of the gas increases when TiCl4 gas molecules are inserted into armchair carbon nanotubes. The adsorption of TiCl4 regulates the electronic structure of carbon nanotubes, significantly improves the density of states near the Fermi level, enhances the conductivity of the composite, has no significant effect on the size of the pseudo-energy gap, and the peak position is still determined by the carbon nanotubes themselves. The adsorption of TiCl4 has a limited effect on the optical parameters of the system. While enhancing the conductivity of the composite, it does not increase the absorbance, reflectivity and loss function values in the visible region, which can effectively improve the performance of transparent conductive films.