An apparatus and a method for sensing a display panel are provided. The apparatus includes a source driving circuit and a sensing circuit. The source driving circuit is coupled to data lines to drive the pixel circuits according to a display period comprising frame periods. The sensing circuit is coupled to a plurality of pixel circuits. The sensing circuit senses characteristics of the pixel circuits in the test data periods of the display period. The test data periods are periodically arranged in the display period. In each of the test data periods, a corresponding pixel circuit receives test data, and the sensing circuit senses the electrical characteristic of the corresponding pixel circuit. In the scan-line periods of each of the frame periods, the corresponding pixel circuit receives display data from a corresponding data line, and the sensing circuit does not sense the corresponding pixel circuit.