Based on the method of real-time background noise compensation,a lidar for visibility measurement,named as laser visibility meter is designed. The system adopts a modular design concept,and takes the embedded computer PCM-3370 as the control and data processing core. To deal with the signal-to-noise ratio degrading under the strong background light,a new method that combines the real-time background noise compensation with the moving average method using threshold segmentation is adopted to process the signal,which greatly improves the signal-to-noise ratio. Finally,the accuracy and effectiveness of the design is verified by numerical simulation and field tests.