A tunable metamaterial filter is designed based on split-ring resonators (SRRs) in this paper. The metamaterial filter has a compact size of 15 mm×20 mm, and miniaturization is realized by using the SRRs. By loading tunable devices, the continuous operation of the filter is realized at X band (from 10.7 GHz to 12 GHz), the bandwidth is about 13%, the minimum return loss is 35 dB, and the maximum insertion loss is 0.37 dB. The results illustrate that the metamaterial filter shows the compact size, wide bandwidth and good band pass characteristics.