The experiment of randomized effectiveness evaluation of weather modification was conducted in 2015 an 2016 through the warmcloud smog generators at Bawang Mountain of Hainan Province. The test samples were randomly distinguished into 2 groups (seeded and noseeded), with a total number of 34. The statistical and physical effectiveness of all the test samples is analyzed with the data from the local automatic rainfall stations, Doppler radar and TITAN system, and the results are as follows: The average absolute rainfall improvement of the unseeded test samples is 2.97 mm per 2 hours, and the average rainfall improvement of the seeded test samples is 3.364 mm per 2 hours. The significant analysis of test samples indicates that the target cloud rainfall data between seeded and noseeded test samples are totally different; the physical effectiveness is analyzed with the data of the Doppler radar and TITAN system, and the physical evidences of warmcloud weather modification are evaluated by analyzing the difference between maximum combined radar reflectivity after the seeding moment. The results show that the maximum combined reflectivity, liquid water content and maximum echo height of the seeded group tend to grow stronger than theses of the noseeded group in the developing stage of cumulonimbus clouds. In the weaken stage of cumulonimbus clouds, the weaken trend of echoes tends to be abated in most of the seeded test samples.