In this paper,it is described that the uncertainty of evaluation results of DC gain and offset of linear measurement system by using the terminal-based straight line method,including the courses of analysis and evaluation of uncertainty.Some error sources of evaluation are discussed,including the errors of signal source,the measurement errors of the calibrated system,the influence of quantization error of calibrated system,the environment influence,and so on.Both the DC gain uncertainty and the offset uncertainty of terminal-based line measurement systems are given out.For an example of experiment,the analysis and uncertainty evaluation results of both DC gain and offset by using the method in this paper is presented.The verification of the uncertainty has proved the correctness and feasibility of the above method.The courses and conclusion proposed can be applied to the uncertainty evaluation of measurement standards of both DC gain and offset.