In order to analyze the error of the measuring co-ordinates of shots with sky screen in ballistic trajectory and evaluate the accuracy of survey parameter, the creating factor and transitive relationship of parameter error were studied according to the sky screen structure and principle of measuring co-ordinates of shots with sky screen. Moreover, the parameter error of measuring co-ordinates of shots with sky screen was analyzed based on the parameter of experiment, and the error scope of the five measuring parameters was calculated in theory. Through the fire experiment, the target pitch angle, azimuth, and coordinates of measuring system are basically the same to the paper target, the velocity is the same to the other testing instrument, and the error is in the scope of analysis. The experiment proves that, the measuring co-ordinates of shots with sky screen in ballistic trajectory are high precision and stable reliable measuring instruments.