The invention discloses a wastewater processing method of hydrolysis-acidification enhanced by addition of zero-valent iron (ZVI), including the following steps: 3˜6 ZVI-filling layers are settled in the middle of an anaerobic hydrolysis-acidification reactor. Excess sludge taken from sewage treatment plant using as seed sludge is added into this anaerobic hydrolysis-acidification reactor for startup and domestication. In the present invention, ZVI are added into this anaerobic hydrolysis-acidification reactor to accelerate organic matters degradation and produce more acetic acids, accompanied with higher COD removal obtained. ZVI can be protected from rust in this anaerobic biological environment due to the air isolation. Also, ZVI can enhance anaerobic hydrolysis of wastewater through reducing refractory pollutants involved in wastewaters. This novel method made the effluent from the hydrolysis-acidification reactor present less COD concentration and simpler substrate form, benefiting for the following anaerobic methanogenesis or aerobic treatment.