Ethereum is a very popular blockchain platform. However, due to the limit of the Transaction Per Second (TPS) of this platform, the transaction processing time in Ethereum is very slow, which greatly affects the user experience and wastes time and other fees. Therefore, the scalability of Ethereum becomes an urgent problem to be solved. In this study, we try to improve the scalability problem of Ethereum by building a layer 2 with the zk-Rollup protocol. An evaluation of the implementation is also conducted. Experimental results show that the cost of transactions decreases depending on the batch size, with the gas cost decreasing by more than 85% for a batch size of 50 transactions. Other evaluation results reveal that deposits incur the most cost and increase faster with the batch size.