The charge transport parameter φμτ of the photorefractive crystal barium strontium titanate (Ba1-x SrxTiO3, BST) has been measured by means of two-beam coupling technique. The photorefractive response time for an intensity of 1 W/cm2 at 515 nm has been determined to be 0.5 s. The functional variable for the rate of grating formation has been corrected by taking into account of intensity-dependent absorption coefficient of the crystal. The fitted values of the dark conductivity σd and the charge transport parameter φμτ have been obtained to be 1.0×10-11 (Ωcm)-1 and 2.8×10-10 cm2/V, respectively.