Abstract: According to the problem that the occurrence of rock burst has the characteristic of lag, the analytical method was used for establishing instability theory of isolated coal pillar creep. Based on the theory of rock burst instability, the mechanism of instability of isolated coal pillar creep and creep instability criterion were founded. Assumption of coal pillar roof with creep properties, creep instability criterion of isolated coal pillar was proposed. On the basis of the function relationship of roof stiffness variation with time in the model like H, M, K, K-V, P-T, B body and isolated coal pillar creep instability criterion, we get isolated coal pillar rock burst creep instability conditions and the theoretical formula of isolated coal pillar rock burst lag time and roof kick. Combined with practical engineering, the isolated coal pillar rock burst lag time and the theoretical value of roof kick were compared under the conditions of different creep models. Results showed that the B model coincided well with the engineering practice, but smaller than the actual value, which illustrates that the theory model has some limitations, studying a kind of creep mode that is more in line with the engineering practice is needed.