Abstarct: Solar energy is one of the renewable energy sources. Perovskite solar cells, as the third generation of solar cells, has recently developed rapidly and their energy conversion efficiency has reached about 21%. For these cells, the electron transfer laxyer plays an important role in electron transfer and preventing electron-hole recombination. Titanium dioxide (TiO2) is preferred as the electron transfer laxyer due to its excellent optical properties and the 3/2eV bandgap. However, TiO2 has disadvantages such as low quantum efficiency and recombination of carriers, which can be remedied by surface modification and fabrication of a proper composite with other semiconductors. In this study, two nanocomposite including TiO2/SnO2 and TiO2/ZrO2 with a different weight percentage of Sn and Zr, respectively, were synthesized using chemical routs. The structural, optical, and morphological characteristics of the synthesized samples were studied by X-ray diffraction (XRD), Raman, UV-VIS spectroscopy, photoluminescence, and field emission electron microscopy (FESEM) techniques. To fabricate a perovskite solar cell, the three cationic perovskite of Cs0.05(MA0.17FA0.83)0.95Pb (I0.83 Br0.17)3 was used as adsorbent, TiO2/SnO2 nanoparticle paste was utilized as mesoporous laxyer and carbon paste was used as a cathode. The solar cells made were characterized by a solar light simulator with the best efficiency of 8.35%. Then, for the synthesis of the TiO2/ZrO2 nanocomposite, different amounts of ZrO2 nanoparticles were added to the TiO2 paste. After characterization of the synthesized nanocomposites, perovskite solar cells were fabricated by repeating the previous fabrication process and replacing the TiO2/ZrO2 nanocomposites with the TiO2-SnO2 mesoporous laxyer. The best energy conversion efficiency using TiO2/ZrO2 as a mesoporous laxyer was reached to 13.13%.