Based on the input structure of detonating fuse assembly in long channel three-level explosive train and factors related with boosting reliability,the input of detonating fuse assembly in short channel two-level explosive train was designed. The input was filled with PETN explosive (the mass was 100 mg,the density was 1.55 g·cm^－3）,the gap between electronic intitator and the input was 1.7 mm,and the input contacted with confined detonating fuse directly. The results show that the input of detonating fuse assembly is reliable and has high detonation transfer margin.