Thin films of porous (Ba, Sr) TiO3 ceramic (BST) have been grown on Ti electrodes in aqueous solution of (Ba, Sr) (OH)2 by hydrothermal-electrochemical method. X-ray diffraction data of as grown films shows the presence of four different peaks corresponding to barium strontium titanate. The scanning electron microscopy (SEM) shows a uniform distribution of spherical crystallites. The conduction humidity characteristic indicates that the electrical conductivity of the sample is enhanced by the physical adsorption of water molecules. The real part of the complex dielectric constant also increases with relative humidity. It indicates that multi-physisorbed relative layers of water are formed with the increase in humidity. The time taken by the sample to achieve 90% value of total change is defined as the response time in the case of adsorption and recovery time in the case of desorption. The measured response and recovery times from the characteristics are less than 5 and 265 seconds respectively.