Developing functional textiles with thermal insulation and hydrophobic properties is of significant interest. This study successfully synthesizes K2Ti6O13 (potassium titanate, KTO) whiskers via the hydrothermal method and prepares KTO composite silica polyester fabric (KSP) through impregnation technology, exhibiting excellent thermal insulation and hydrophobic qualities. X-ray diffraction (XRD) analysis verifies the high purity and excellent crystallinity of KTO whiskers and SiO2 micro-powder. Scanning electron microscopy (SEM) images reveal that the KTO whiskers retain their original morphology and exhibit uniform size distribution, with an average length of around 1 μm and an aspect ratio of 40. Transmission electron microscopy (TEM) images further validate the planar growth properties of the whiskers. Raman spectroscopy research elucidates the vibrational modes of various chemical bonds in the KTO whiskers. The ultraviolet–visible–near-infrared spectrophotometer test results demonstrate that the KSP fabric reflects 43.5 % more light than standard polyester fabric and substantially lowers the temperature in the covered chamber under simulated sunlight exposure, achieving a maximum reduction of 7.4 °C. The KSP fabric has exceptional hydrophobic properties, completing a contact angle of 153.2° and maintaining reflectance stability, with a mere 5.92 % reduction after 20 days of outside exposure. This work offers substantial reference value for the advancement of practical textiles.