The microfluidic chip-based system in conjunction with the t-test, was found applicable to identify the polymorphic RAPD fragments from P. Taiwanensis Hayata, whose polymorphism was weak and the sizes of each allele were unknown. The suggested microchip electrophoresis was very sensitive, and it requires much less sample and only a quarter of the time compared to the agarose gel method. The standard deviations of the fragment sizes and peaks area, for replicates number 10, ranged from 0 97%(701 bp) to 1%(301 bp) and 10%(301 bp) to 11 9%(701 bp), respectively. The average values of three alleles in the polymorphic RAPD fragments were identified as 301, 708 and 1069 bp with standard deviations of 3, 7, and 12 bp.