In this paper, a technique called Time-Varying Texel (TVT) is presented for simulating the withering effects of grassland. Time-Varying Texel is defined as an extension of the traditional texel structure by adding a time dimension, where the texel at different time is computed by using a Texel Deformation Technique. In this approach, a point based structure (PBS) is employed in combination with the Time-Varying Texel. Throuogh the introduction of PBS as a bridge, a Physical-biological Model can be applied to handling the deformation at the grass texel. In addition, a mingling algorithm is applied to enhance the diversity of grassland, and the LOD representation of TVT is developed for promoting efficiency. Experimental results show that the realistic grass time-varying simulation is well achieved with the proposed techniques.