The invention provides a calibration device of a sub-pixel circuit, a source electrode driver and a data voltage compensation method. The sub-pixel circuit comprises a driving transistor, a data line and a sensing line. The calibration device comprises a capacitance measurement circuit, a charge detection circuit and a parameter calibration component, wherein the capacitance measurement circuit is used for outputting capacitance measurement voltage which is related with sensing line capacitance of the sensing line; the charge detection circuit is used for detecting capacitance charging voltage on the sensing line capacitance of the sensing line under the condition that reference data voltage is applied to the data line; and the parameter calibration component is used for calculating an electrical parameter of the driving transistor according to the capacitance measurement voltage, the reference data voltage and the capacitance charging voltage. Therefore, an electrical parameter drift condition of the driving transistor in the sub-pixel circuit can be determined, and thus data voltage applied to the sub-pixel circuit can be adjusted according to the electrical parameter drift condition, so that a circumstance of non-uniform display brightness caused by electrical parameter drift is compensated.