We have investigated the phase transition of Bi 1.8Pb 0.2Sr 2CaCu 2O 8 samples with specific heat in low temperature. The phase transition temperatures depend on the oxygen contents. There is a relation between the specific heat anomaly and the oxygen contents in these samples. The specific heat anomaly peak is the largest for the optimum doped sample, the anomaly peaks are decreased for the underdoped samples. There are the phase segregation phenomenon when the oxygen is removed content in these Bi2212 system samples, their transition temperatures are about 60K and 90K. The peak of specific heat anomaly for the overdoped sample (Tc=60K) does not appeared. The resistance measurement shows that the phase transition temperature of these samples are the same as that of the specific heat measurement. The electronic specific heats C e and the Debye temperature θ D are calculated.