In order to improve the calculation speed of ultrasound elastograms, two common ultrasound elastography methods based on Graphics Processing Unit (GPU) were investigated. After giving an introduction about the two common methods, the GPU-based approaches to rapidly estimate tissue strain was proposed. The two GPU-based approaches were tested in simulation signals and real signals by scanning a tissue-mimicking phantom respectively．Experimental results show that the GPU-based Normalized Cross Correlation (NCC) implementation is about 42 times faster than that based on CPU platform with the same elasticity image quality. At the same time, the GPU-based Phase Zero Estimation (PZE) approach is about 65 times faster than that corresponding implementation on CPU by increasing data throughput.