The present invention relates to a detoxifizyme with the activity of transforming aflatoxin and the gene encodes thereof. Firstly a novel protein is isolated and purified, named aflatoxin-detoxifizyme (ADTZ), which has the activity of transforming aflatoxin. The ADTZ gene is obtained through specific primers, and the gene is purified and sequenced. The gene encoding of ADTZ is cloned from the total RNA of Armillariella tabescens. The recombinant protein is expressed and purified through various expression systems using genetic engineering methods. The said detoxifizyme has bioactivity of transforming AFB.sub.1, reducing mutagenic effects of AFB.sub.1. It has great potential for the manufacturing of feed or food and development of anti-tumor medicament.