Ph-ADC uses quadrature IQ channels to extract phase information, but IQ channel offset errors will cause the system’ s bit error rate (BER) to increase. Aiming at the above problems, a method of extracting I/ Q offset error based on frame sampling is proposed, and the trapezoidal integration method is used to compensate. Relative to the traditional method, this method can save time wasted due to memory access, data delay, and the system’s interrupt response to each sample. The proposed phase domain ADC offset error detection and compensation technology is verified by establishing a π/ 4 DQPSK demodulation, 6-bit Ph-ADC, Eb / N0 of 12 dB digital modulation system. The simulation results show that when the input signal frequency is 450 kHz, the I/ Q offset error is 10%, the signal-to-noise distortion ratio (SNDR) of the system is increased from 7. 02 to 37. 22 dB, the spurious-free dynamic range (SFDR) of the system is increased from 17. 37 to 38. 74 dB, and the ENOB is increased from 1. 03. After calibration, this method can reduce the BER of the system to the order of 10 -5 and make the error vector magnitude (EVM) less than 15 dB.