In this paper, the internal friction behavior and thermal conductivity of Fe-base bulk metallic glass (BMG) with different crystallization have been measured by multi-function high-precision internal friction instrument and laser flicker thermal conductivity instrument. The internal friction behavior of Fe45Cr15Mo14C15B6Y2Ni3 BMG is divided into three stages: high strength region, superplastic region and crystallizing region. With the increase of crystallization, the superplastic and crystallizing region gradually weaken, while the thermal conductivity is gradually enhanced. Until the disappearance of the two regions, the BMG were crystallized completely and the thermal conductivity was enhanced obviously. By means of TEM analysis, it was found that after partial crystallized, the medium-range order (MRO) was formed in the disordered atoms of BMG, and after complete crystallization, a large number of serried nanocrystallines with a diameter of 20 similar to 80 nm were precipitated, which is closely related to the significant increase in thermal conductivity.