Abstract: ObjectiveTo develop a portable body balance testing system for posture of standing and sitting.MethodsAs the body sways, balance indicator fixed on the centre of head will change with the swaying. The tract of the swaying indicator will be translated to tract of the posture by the means of photo-electricity and image processing. The body balance function will be measured quantificationally after the tract is analysed.Results and ConclusionThe system has been developed. With the aid of this instrument, the body balance function of one volunteer pre-drinking and post-drinking has been measured and compared.

Key words: balance function, function measure, testing system, photo-electricity, image processing, track, posture