The attitude measurement data in the vertical take-off phase of a rocket is of great significance to analyze the running orbit, aerodynamic parameters and flight control performance of rocket. The traditional attitude measurement of rocket vertical take-off phase mainly includes telemetry, optical measurement, and radar measurement. The violent vibration has a great impact on the attitude measurement accuracy of telemetry, and once the rocket takes-off fails, it is difficult for telemetry method to obtain effective original analysis data. Although the optical measurement accuracy is high, it needs to use multi station optical equipment to interpret the rocket attitude data after rendezvous, so the real-time performance is poor, and the optical equipment is vulnerable to the interference of weather environment and tail flame during take-off phase, so there is a risk of missing rendezvous data. Although radar measurement is little affected by weather conditions, it is easy to be disturbed by ground clutter. Therefore, there is no external real-time attitude measurement data in the rocket vertical take-off phase. It is urgent to fill the data gap in this phase through new measurement methods to ensure the safety of the rocket vertical take-off phase.Aiming at the technical problems of external real-time attitude measurement in rocket vertical take-off phase, considering the advantages of Lidar, such as high precision, all-time measurement, high resolution and not easily disturbed by environment, the real-time attitude measurement method in rocket vertical take-off phase based on Lidar is proposed in this paper. Raytheon intelligent MS03-A500 four wire Lidar is adopted, and the Lidar is installed on the two-axis tracking frame to form the measurement system. Before the rocket is launched, the Lidar continues to scan the middle and upper part of the rocket to obtain the static laser point cloud data, correct the point cloud data and solve the spatial coordinates, and adopt the multi ellipse center fitting central axis algorithm. It is calculated and analyzed that the static and dynamic attitude measurement accuracy of Lidar are 0.018 8° and 0.049 8° respectively. In the rocket launch test, the Lidar measurement system is arranged at a launch site 150 meters away from the rocket. In the rocket vertical take-off phase, the Lidar tracks and scans the fixed position of the rocket with high precision, and obtains the rocket attitude change value with real-time and high precision.To verify the reliability and rationality of Lidar measurement data, three sets of optical equipment are used to measure the rocket attitude angle intersection at the same time. After comparing the rocket attitude change values measured by Lidar and optical equipment, the following conclusions are drawn: 1) According to the measurement accuracy calculation results and the verification of test data, the attitude measurement accuracy based on Lidar is about 5 times higher than that of optical measurement equipment. 2) Considering the different measurement accuracy of the two equipment, the variation trend of rocket yaw angle and pitch angle measured by Lidar and optical equipment is basically the same in this test, which verifies the correctness and rationality of the attitude measurement methods and measurement accuracy of the two kinds of equipment. 3) The real-time high-precision attitude measurement and data output of the rocket based on Lidar is realized, which effectively fills the gap of a real-time attitude measurement outside the rocket, provides a real-time attitude data source for security control equipment, and ensures the launch safety of the rocket.