The invention relates to a cross recessed female inner conductor precise sealing device and method. The sealing device includes a power supply module for providing electric energy, a motor driver, a motor, a driving wheel, a transmission belt, at least one driven wheel, conical rollers and a working platform. The power supply module, the motor driver and the motor are fixedly mounted on the working platform. The driving wheel is connected rotatably on the working platform and is driven by the motor. The driven wheel is connected rotatably on the working platform. The driving wheel drives the driven wheel through the transmission belt. The conical roller is connected rotatably on the driven wheel. Each driven wheel is provided with three conical rollers arranged in an equilateral triangle. According to the invention, the sealing dimension precision and consistency are ensured, no damage is caused in the sealing process, and the universality is high.