In this paper,the present situation of the site calibration of the aircraft ground measuring and testing system is reviewed and the requirement situation of the site calibration is induced and summarized,including the requirements of traceability,on\|line evaluation requirements,mutiple physical quantities calibration requirements,mutiple characters calibration requirements,automation calibraiton requirements and over\|all evaluation requirements.Begine with the technique,metrological rule and mentality,the difficult points within them are analyzed,including the in\|site calibration multiple quantitiess exciting source,automation calibration,measurability,rules' adaptability,compound dimension characteristics and quality mentality,and the relative countermeasures and suggestions are proposed,including the overall evaluation countermeasures,the disign principle of measurability of in\|site measuring system and the multistage calibration scheme.