Abstract: In order to reveal the yak kidney cells' poison rational influence under the stress of heavy metal,in the produce of kidney cells with different concentrations of heavy metal ions of lead( Pb~2+) and cadmium( Cd~2 +),metallothionein mRNA expression of yak kidney cells were detected by Real-time PCR.It showed that the value of sample after added five different concentrations of heavy metal lead were 0.489,0.603,0.796,3.031 and the value of sample of the five different concentrations of heavy metal cadmium were 5.28,3.53,8.11,11.63,respectively,when adding different concentrations of heavy metal 0,5,10,20,30 μmol / L into the yak kidneycells. The result showed that it had obvious inhibitory effect on growth when added 10 μmol / L Pb~2+and Cd~2+into the kidney cells,and the corresponding amount of mRNA expression of metallothionein was relatively high,and the toxicity of heavy metal Cd~2+was stronger than Pb~2+comparing to the relative expression of mRNA,and the toxicity of cells was reduced by combining MT when heavy metal content was relatively low.