Mycoplasma DNA in nasopharynx secretion from seventy pediatric mycoplasma cases was detected, using rapid feit of PCR DNA sample preparation method and simple PCR processes. The result of PCR showed that: fifty-three positive cases with a positive rate 75.7%, comparing with only 53.8% positive rate using mycoplasma culture method (P < 0.05). Thirteen PCR positive patients were treated by Venoclysis Erythromycin for 10-14 days but mycoplasma DNA was identified by PCR again. Among them, eight cases turned negative, but five cases still remained positive. The resalt showed that this method was not only more sensitive and reliable than conventional culture techniques, but also could simplify the PCR processes. It could be used for routine mycoplasma pneumonia test and for early diagnosis, which leads to early treatment and evaluation of therapeufic effect.