Based on the principle of intersection measurement, a mathematical model is established to gauge the location and the size of the sailing ships, and the formula of measurement error is deduced. The distribution of the measurement error is simulated using Matlab software, and the main factors affecting the system measurement accuracy are analyzed. The measurement model is validated through the tests. The results show that it is feasible to use the intersection measuring principle to measure the location and the size of sailing ships. It also lays the foundation for further project application.