Two different thermo-sensitive materials are acquired by diffusing metal Mn into p-type Si monocrystal of 5Omega · cm and n-type Si monocrystal at high temperature. The measurment results indicate that their coherence is good when diffusing temperature and time is proper. Materials of low PTC can be obtained by diffusing Mn into n-type Si. Its B-value is about 620 K; and NTC materials can be acquired by doping Mn into p-type Si. Its B-value is 4 200～4300 K.