Horizontal torsion balance impulse device is an effective approach to study the impulse couple produced by laser and working materials ablation. The measuring process was susceptible to the noise so that the analytical method for the way how the noise impacted on the system parameters calibration error and the impulse measuring error was put forward. The method was using the Monte Carlo number simulation method according to the relationship between the system parameters calibration error and the signal-to-noise ratio and the relationship between the impulse measuring error and the signal-to-noise ratio based on impulse instantaneous effect. This method can be used to analyze the influence characteristics how the noise impacts on the system parameters calibration error and the impulse measuring error so as to provide practical suggestions for the error analysis and the structure design.