γ-Al₂O₃ was used as the carrier, the group VIII metal oxides and the sub group metal oxides were used as active components, and the γ-Al₂O₃ catalysts were prepared by the equal volume impregnation method. Hydrogen rich fuel gas and tar products were produced by the mixed pyrolysis of coal and catalysts in a furnace. The influence of γ-Al₂O₃ catalysts with different loading Cr₂O₃ on the mixed pyrolysis products of coal was studied. The catalyst was characterized by ICP-MS, XRD and BET, and the pyrolysis mechanism of coal and catalyst was studied. The results showed that: 1) The tar and gas of coal pyrolysis were 0.32g and 1.58g, respectively, and the highest total contents of CO, H₂ and CH₄ were 71.40% respectively. 2) Fe₂O₃/γ-Al₂O₃ catalyst made the highest tar of 0.75g, which was 16.4% higher than that of coal; Cr₂O₃/γ-Al₂O₃ catalyst made the highest gas of 1.73g, which was 9.5% higher than that of raw coal. 3) The Cr₂O₃/γ-Al₂O₃ catalyst prepared by loading 1% Cr₂O₃ had better catalytic effect. 4) The the specific surface areas of Cr₂O₃/γ-Al₂O₃ and γ-Al₂O₃ were similar, while the catalytic cracking effect of Cr₂O₃/γ-Al₂O₃ was more obvious than that of γ-Al₂O₃, so Cr₂O₃ improved the catalytic activity.