The aim of this study was to investigate the feasibility of using RASSF1A gene as a universal fetal marker in maternal plasma. Two methods of circulating cell-free fetal DNA (cffDNA) extracted from maternal plasma were compared. The better one was chosen for extraction of cffDNA in the 20 pregnant samples. The SRY gene and the RASSF1A gene treated with methylation-sensitive restriction enzyme were amplificated by RT-PCR and the PCR system was optimized. The results showed that the SRY gene was found in 11 out of the 20 pregnant samples, which was consistent with the postnatal sex. Using the optimized PCR system, the specifically amplified fetal-associated methylated RASSF1A gene was found after treatment with BstUI in 18 of the 20 pregnant samples, while the 2 samples failed in detection. It is concluded that the methylated fetal-specific RASSF1A gene can be used as a universal fetal marker for the presence of cffDNA in maternal plasma without fetal gender restrictions. So, it can be used for noninvasive prenatal diagnosis.