Abstract: To improve efficiency and veracity of soil sampling in testing bulk density, the cutting ring method and in situ soil tube method were combined and a multi-segment in situ soil sampler was designed. This soil sampler was composed of sampling device and sampler separation device. The results show that the method of multi-segment in situ soil tube can effectively guarantee undisturbed sampling soil and improve sampling efficiency by 400%～800% compared with cutting ring method.