The present invention provides an OLED (Organic Light Emitting Display) panel sensing system and an analog-digital conversion error correction method thereof. Each source driving chip of the system has two sampling channels which are internally connected, a plurality of source driving chips are connected in order through the sampling channels, when the analog-digital conversion error correction is performed, a timing controller controls the source driving chips to perform analog-digital conversion of reference voltage to obtain reference data so as to perform calculation to obtain error data and store the error data in the source driving chips, the timing controller controls the source driving chips to receive sensing data transmitted by the OLED panel and perform analog-digital conversion, the converted sensing data is corrected according to the error data stored in the source driving chips, and corrected sensing data is output to reduce the pressure drop of the reference voltage on a routing while realizing correction of the analog-digital conversion errors and avoid the problem of error data loss caused by replacing the timing controller.