Energy　security　and　environmental　pollution　are　two　major　concerns　worldwide.　H2　from　pyrolysis/gasification　of　biomass　and　waste　plastics　is　a　clean　energy　source.　However,　relatively　low　yield　and　composition　of　H2　is　produced　using　this　technology,　thus　preventing　its　commercialisation.　Catalyst　is　key　to　promote　H2　production.　This　paper　aims　to　explore　whether　newly　developed　dual-support　catalyst　Ni-CaO-C　can　catalyse　gasification　of　volatiles　from　pyrolysis　of　different　plastics　(e.g.　high　density　polyethylene　-　HDPE,　polypropylene　–　PP　and　polystyrene　-　PS)　and　biomass　(e.g.　pine　sawdust)　for　H2　production.　Experiments　with　and　without　catalysts　were　performed　to　test　the　performance　of　catalyst　Ni-CaO-C.　Impact　of　changing　operating　conditions　(i.e.　feedstock　ratio,　reforming　temperature　and　water　injection　flowrate)　on　H2　production　were　also　investigated.　Results　show　that　catalysts　(Ni-Al2O3　or　Ni-CaO-C)　can　effectively　promote　H2　production.　The　H2　production　using　catalyst　Ni-CaO-C　is　much　better　than　catalyst　Ni-Al2O3.　The　catalytic　effect　of　Ni-CaO-C　rank　in　the　sequence　of　HDPE　＞　PP　＞　PS.　Plastic　content　in　feedstock　is　suggested　to　be　less　than　40　wt%　(for　HDPE　and　PP)　and　30　wt%　(for　PS)　when　mixing　with　biomass　to　reach　high　H2　production.　When　the　feedstock　ratio　is　constant,　high　H2　yield　(i.e.　80.36　mmol/g)　is　achieved　under　relatively　low　reforming　temperature　at　700　°C　and　water　injection　flowrate　at　5　mL/h　for　HDPE.　However,　under　the　same　conditions,　PP　and　PS　only　have　H2　yields　at　59.35　mmol/g　and　38.51　mmol/g.　PS　requires　even　higher　temperature　(800　°C)　and　water　injection　flowrate　(10　mL/h)　to　ensure　acceptable　H2　yields.　The　new　findings　presented　in　this　paper　can　help　large　scale　commercial　application　of　pyrolysis/gasification　technologies　for　biomass　and　waste　plastics.　©　2020