In the present approach, a Cr2O3-TiO2-modified, portable, and biomimetic nanosensor was designed to meet the requirement of a robust and colorimetric sensing of hydrogen peroxide. Cr2O3-TiO2 nanocomposites prepared via the hydrothermal method were fabricated as a transducer surface on the filter paper using the sol-gel matrix. The color on the filter paper sensor changed from green to blue upon the addition of hydrogen peroxide in the presence of TMB. This change in the color intensity was linear with the concentration of H2O2. RGB software was used as a color analyzing model to evaluate the optical signals. This paper-based colorimetric platform provided us with an improved analytical figure of merit with a linear range of 0.005-100 μM with 0.003 μM limit of detection. The real sample analysis and excellent anti-interference potential results proved the good analytical performance of the proposed design, providing a more promising tool for colorimetric H2O2 detection. Introducing Cr2O3-TiO2 nanocomposite-based paper sensors, being a novel method for optical and colorimetric detection, can pave the way for the development of other sensing devices for the detection of different analytes.