The kinesin motor walking on microtubule lattices can cause disassembly of GDP-tubulins, generating defects, and repair the defects by incorporating GTP-tubulins. To explore the underlying mechanism, a model is proposed here. On the basis of the model, the dynamics of the defect generation, defect repair and tubulin exchange induced by the kinesin motor is studied theoretically. The theoretical results explain well the available experimental data. Moreover, predicted results are provided.