Micropayment systems in existence usually do not provide fairness, which means that either the customer or the merchant, or both, can cheat each other and gain a financial advantage by misbehaving in the protocols. This paper proposes a new fair micropayment system based on hash chain, which is an off-line, prepaid system and supports divisibility of digital coins in a simpler way. Moreover, in our system, a hash chain can be used to have transactions with different merchants. Compared with other micropayment schemes, e.g. PayWord, no public-key operation is required, which improves the efficiency of our system. In addition, restricted anonymous is provided in our system.