Abstract: The influence of ZnCl₂,a centrifuge-separation liquid,to Rock-Eval pyrolysis was studied.Coal sam ple were collected from Yu-Feng mine in San-Hsia area,northern Taiwan.The sample was crushed and then divided into three parts namely P₁,P₂ and P₃ respectively.P₁ is the original coal sample;P₂ had been immersed in ZnCl₂ liquid and then dried up in room temperature;P3 is similar to P₂,but had been water washed be fore drying up.Preliminary results show that both S₁ and S₂ were evenly distributed in coal par ticles.Significant differences in S₁,S₂,Tmax,TOC and HI was observed for P₂ sample,but not I_p(production index)value.After cleansing ZnCl₂ by water-washed,P3 showed that the previous pyrolysis pa rameters,except Ip still dropping,can be resumed to those of P₁.