After the flight test of a certain project is completed, two problems were found while conducting the interpretation of telemetry data. Firstly, under the condition of a stable external environment ,the fluctuation range of the original code of a certain telemetry parameter can reach 4 to 5 layered values. Secondly, the telemetry parameters of the four suspended wave channels are non-zero and different constant values. Based on problem location and mechanism analysis, this paper proposes a method for improving the accuracy and stability of parameter acquisition based on charge discharge. This method effectively solves the above two problems that have long plagued the measuring system. Moreover, it has the advantages of small modification and low cost, and has the value and broad prospects for promotion and application to other projects with analog quantity acquisition functions.