Abstract: Objective: To setup the protocol of multiplex PCR which suit the synchronizing hybridization and cutoff of signals discrimination.Methods: Optimisation of the primers and probes had been done;some key characteristics to PCR were adjusted and the final strategy was done.Preparing the oligoneucleid microarray,cutoff to determine wildtype and matant alleles was calculated.Results: It was recommended that ratios of wildtype allele to mutant signal which was higher than 4 or lower than 2.5 which be used as cutoffs in determination.When the ratio was in the range from 2.5 to 4,PCR or hybridization should be rerun.Conclusion: Multiplex PCR and synchronizing hybridization are helpful in epidermetology;the advantages of genechip is showed in CYP450s study by these techniques.