The present invention provides a source driver for use in a TFT-LCD, comprising: a data register, a data latch, a digital-to-analog converter and an output buffer. A first loading pulse is provided to the output buffer, such that the output buffer starts to output the gray-scale voltages of odd output ends to corresponding TFT sources in response to a second edge of the first loading pulse from the second level to the first level, which second edge immediately follows the first edge, and a second loading pulse is provided to the output buffer, such that such that the output buffer starts to output the gray-scale voltages of even output ends to corresponding TFT sources in response to a second edge of the second loading pulse from the second level to the first level, which second edge immediately follows the first edge. At least the second edge of the first loading pulse is not synchronous with the second edge of the second loading pulse. A driving circuit and a driving method are further provided. The source driver, the driving circuit and the driving method can alleviate adverse consequences resulting from too large difference between display data of two adjacent rows.