In　this　paper,　a　wide-stopband　high-temperature　superconducting　(HTS)　bandpass　filter　(BPF)　is　presented　using　slitted　stepped-impedance　resonators　(slitted-SIRs).　The　use　of　SIR　is　essential　in　widening　the　filter　stopband.　Besides,　it　is　found　that　introduced　slits　in　SIRs　provide　additional　freedoms　to　control　resonance　modes　when　compared　with　a　conventional　SIR.　Hence,　four　types　of　slitted-SIRs　are　arranged　at　same　fundamental　mode　f(0)　and　different　higher　order　modes　by　adjusting　the　slits.　The　coupling　of　higher　order　modes　is　reduced　and　wide　stopband　is　achieved.　In　addition,　a　composite　spurline　structure　is　employed　to　generate　two　independently　controllable　transmission　zeros,　which　further　improves　the　stopband　performance.　Finally,　a　cascade　quadruplet　HTS　BPF　is　designed　and　fabricated　on　an　MgO　wafer　with　double-sided　YBCO　films.　Measurement　shows　the　passband　of　the　BPF　is　operated　at　2.35　GHz　and　its　minimum　insertion　loss　is　less　than　0.15　dB.　The　rejection　level　is　better　than　21.9　dB　in　the　stopband　up　to　13.26　GHz　(about　5.64　f(0)).　The　designed　HTS　filter　tends　to　the　potential　application　for　the　desired　wide　stopband　and　the　high　selectivity　performance.