Aiming to the calibration requirements for degree of linearity, repeatability and slowmoving, the scheme of virtual instruments and USB data acquisition technology is put up. Through force sensors, signal conditioning device, data acquisition card, force loading device, upper computer, and system software, the system realize the automatic calibration. The calibration software can realize the succession data acquisition, data analyzing and result display. According to calibration standard JJG144-2007, the system we developed has high precision below 1%. The project can provide a new kind technology for the dynamic and continuing calibration for force sensors.