This paper investigates a coordinated inventory and pricing problem with the e-retailer's price-protection service over multiple periods. By solving a stochastic dynamic programming in the two-dimensional state space, the optimal policy is fully characterized. Specifically, the inventory policy is a previous price-dependent base-stock policy. The pricing policy: as the previous price increases, the optimal current price stays unchanged first, then increases, and finally decreases. Numerical results indicate that with the impact of the price-protection service increasing, the base-stock level and current price rise under some conditions. Moreover, the price-protection service benefits the e-retailer when its impact is large enough.