Calcined copper slag (CCS) catalytic steam reforming of jatropha oil was investigated in a fixed bed tubular reactor for hydrogen. The pyrolysis mechanism of jatropha oil was characterized by high performance liquid chromatograph, thermogravimetric analysis, and infrared spectroscopy. At 300–400 °C the fatty acid glycerides cracked into fatty acid, ketene, and acrolein. However, carboxyl, aldehyde, and ketone groups completely became broken bonds when the reactive temperature was 400–500 °C. Dynamic analysis of jatropha oil's thermogravimetric curves was researched by Coats-Redfern equation, where the jatropha oil pyrolysis process accorded with the Z-L-T equation. The activation energy E was 294.14–349.47 kJ/mol, and the pre-exponential factor A was 7.38 × 1020–3.53 × 1025 min−1. Four catalysts were used for catalytic steam reforming of jatropha oil, the active components of CCS were ferric oxide and other metal oxides, and ferric oxide had a good effect on C=C double bond fracture of jatropha oil.