For its high performance and open system architecture, VXIbus based instrumentation has been extensively used in many fields, such as aeronautics, astronautics, electronic communication, transportation, military and so on. As a kind of automatic test device, VXIbus based instrumentation itself should be measured and calibrated. Based on the author's research subject, this paper discusses the necessity and speciality of the calibration. Several solutions are introduced and compared, and an auto calibration system has been built. This paper also discusses the architecture of the calibration software and the control methods for software error. At last, the profound future of the calibration for VXIbus based instrumentation is described.