The homodyne mixing system is used to characterizing the performance of terahertz superconducting kinetic inductance detectors （KIDs）. However， homodyne mixing systems still have issues such as mixer imbalance， measurement system integration， and interference signals. The author designed a new single channel homodyne mixing hardware system and software algorithms to achieve integration of the measurement system， calibration of IQ-mixer imbalance， and performance characterization of KID； Furthermore， noise measurement of KIDs in VNA （vector network analyzer） CW mode is achieved； Finally， the method of hardware circuit design by dual channel homodyne mixing system based on autocorrelation algorithm effectively suppresses interference signals. It is worth noting that these research results are applied to characterize the performance of KIDs， which is important in the design of KIDs arrays.