Based on general imaging conditions, the designed visual vehicle rain sensor can share the on-board camera with other visual vehicle advanced driver assistance system (ADAS) to improve its convenience and economy. In view of the such flaws as false detection, poor detection performance and slow operation speed exhibited by currently used vehicle rain sensors, which are designed for the general imaging conditions, under complicated circumstances, a study has been carried out under general imaging conditions on a visual vehicle rain sensor algorithm for detecting raindrops under blurred background and bright dark partition based on the gradient operator. A comparison has been made between the detection algorithm and other algorithms given in other relative references and research and the results show that, compared with the traditional method, this method effectively reduces the raindrop detection and false detection rate and false negative rate, and effectively improve the speed of image processing.