The paper did a comparative analysis on the socialist countries CO2 emissions, and predicted their total CO2 emissions by 2015 with GM(1,1) model, the results showed that (1) The sort of total CO2 emissions from large to small was the People's Republic of China, Vietnam, DPR of Korea and Cuba. (2) The People's Republic of China and DPR of Korea was mainly dependented on Coal/pea, Cuba was mainly dependented on oil, Vietnam achieved a balance in them. (3) The sort of CO2 emissions per dollar GDP from large to small was DPR of Korea, the People's Republic of China, Vietnam and Cuba. (4) The sort of CO2 emissions per capita from large to small was DPR of Korea, Cuba, the People's Republic of China, and Vietnam. (5) Total CO2 emissions of Cuba and DPR of Korea would decline slightly by 2015, that of Vietnam and the People's Republic of China would increase greatly.