In order to achieve fast and automatic calibration of laser Lidar camera without targets in unstructured environments, this paper proposes a joint calibration method for laser Lidar and camera based on parameter observability self-assessment. Through adaptive keyframe selection algorithm, the calibration solution time is reduced while ensuring the integrity of data information and the basic accuracy of calibration remain unchanged. At the same time, the observability evaluation algorithm is used to evaluate the accuracy of multi lidar joint calibration, establish dataset evaluation standards, and perform secondary calibration when observability is insufficient. The experimental results show that the calibration time of this method is lower than that of the mlcc calibration method, and whether the detection dataset can achieve automatic calibration of multiple Lidars without targets provides a research basis for the fusion of lidar data and camera image data in the future.