The present invention provides a compensation system and a compensation method for AMOLED display. In the system, the initial grayscale data is inputted into the grayscale data converting unit, the initial grayscale data is converted into the initial driving voltage data corresponding to the initial grayscale data by the grayscale data converting unit, and the initial grayscale data is transmitted to the compensation unit; the compensation unit compensates the initial driving voltage data by using the compensation ratio coefficient and the compensation voltage data in the compensation data storage unit and outputs the compensation driving voltage data to the voltage data conversion unit; the voltage data conversion unit then converts the compensation driving voltage data into the compensation grayscale data and outputs the compensation grayscale data to the source driver of the AMOLED display to uniformly compensate the AMOLED display by compensating the initial driving voltage data, which is capable of reducing the required data amount of compensation.