Using conventional meteorological observation data, NCEP 1°×1° reanalysis data, FY-2G cloud imagery, and radar data, the large-scale circulation background, the movement and propagation of the rainband, mesoscale characteristics, temperature, and humidity features of the warm-sector shear line rainstorm on the edge of subtropical high from 25 to 26 June 2018 in Shandong are analyzed. The results are shown below. 1) The warm-sector rainstorm process is generated under the favorable background of the stable and stationary subtropical high, the eastward movement of westerly trough at 500 hPa, the cooperation of low-level jet, and the unstable energy release triggered by low-level warm shear line. 2) The rainstorm area lies between warm shear lines at 700 hPa and 925 hPa. 3) During the rainstorm, small-scale convection cells are triggered in the south of Shandong Province and move northeastward along steering flow with the TBB at cloud top equal to or lower than 60 ℃. 4) Multiple strong echo centers continuously affect the strong precipitation area with obvious train-effect and long duration of strong echo. 5) Infrared cloud imagery can reflect the occurrence, development, and extinction of weather systems. The dark tone area in water vapor image is not obvious and the cold air is weak. 6) The strong development of low-level warm and humid airflow is the main reason for the instability of stratification during the rainstorm process. 7) The main sources of water vapor are the Bay of Bengal and the South China Sea. During the heavy precipitation, there is a jump in water vapor flux with the enhancement of warm and humid southwest air flow. 8) The area covered by TBB at cloud top equal to or lower than 70 ℃ and the negative center of water vapor flux divergence can be used as reference for warm-sector rainstorm forecast.