Abstract: Based on the physical-chemical tests of the soft rocks of Xiaoguanzhuang lron Mine, its mi-crocharacteristics are fuIly analysed. The soft rocks are divided into two classes. The first class is the mid-dle-strong swelling rocks which are mainly composed of montmonllonites. The second is no-swelling rockswhich are mainly composed of green rocks or joint rocks-By the above analyses, the microcharacteristics ofthe soft rock have been researched.