The linear measurement system is the most routine measurement system in the field of chemical analysis and physical testing. According to its linear relationship construction and fitting method, it can be divided into single-point calibration, two-point calibration, multi-point calibration (linear fitting) and standard addition method. Among them, the single point calibration measurement system is often used for analytical methods such as chromatographic analysis, titration analysis, and measurement items such as gas analysis, carbon and sulfur analysis. Two correction factors or relative random errors were introduced to characterize the random effects of conditional variations and system fluctuations on the measurement repeatability of the standard for calibration and the practical sample, and a method and mathematical model for evaluating the uncertainty of single point linear calibration measurement system based on Monte Carlo method (MCM) was proposed. The specific evaluation process and application of MCM was systematically explained based on a case study for determination of hydrogen in TC4 titanium alloy by inert gas fusion-thermal conductivity method. Under the measurement conditions of this paper (the standard repeated 4 times, the practical repeated 7 times), the simulation results was w(H)=(20±3)μg/g, k=2, which was consistent with the result by GUM method. The method and example proposed can be directly applied to the uncertainty evaluation of single-point calibration measurement systems, such as chromatographic analysis and determination of oxygen, hydrogen, nitrogen, carbon and sulfur in solid samples by inert gas fusion-infrared absorption method/thermal conductivity method or high temperature combustion-infrared absorption method. It solved the key issues of MCM applied in the field of chemical analysis to a certain degree, such as the mathematical model construction of measurement system and the introduction of uncertainty from instrument calibration. That is expected that MCM will be applied substantively in the linear measurement system, such as single point calibration, two-point calibration, multi-point calibration (linear fitting) and standard addition method, which will promote the study and application of measurement uncertainty to open up new horizons.