To improve the charge processing capability of longwave infrared detectors, an integrated capacitor multiplexing technology is proposed. This technology divides the readout circuit array into two parts: odd and even rows. The odd and even row pixels are integrated and read out separately. When all odd row pixels are integrated, all even row pixels are not integrated. The odd row pixels reuse the integration capacitance of even row pixels, and after the integration of odd row pixels is completed, they are read out in order of row and column. Similarly, when all even row pixels are integrated, odd row pixels are not integrated, and even row pixels reuse the capacitance of odd row pixels. After integration is completed, even row pixels are read out in order. Compared to the method of using stacked capacitors to improve charge processing capacity, the integrated capacitor multiplexing technology is more effective and not limited by the process. The simulation results show that the integrated capacitance multiplexing technology can increase the equivalent integrated capacitance of pixels to twice the original value, and increase the charge processing ability of the readout circuit from 20 Me^- to 40 Me^-.