Abstract: The cap （PE） and body （PET） of the discarded 550 mL mineral water bottle of Nongfu Spring were used as raw materials. The laboratory-scale fixed-bed reactor and thermogravimetric analyzer were used to conduct pyrolysis experiments to explore the synergistic effects of co-pyrolysis of waste PE and PET plastics and the kinetic behaviors in which co-pyrolysis process was separated into two degradation stages. The results showed that co-pyrolysis of PE and PET plastics promoted the production of liquid pyrolysis oil and improving the selectivity of hydrocarbons in pyrolysis oil. When the mixing ratio of PE and PET was 2∶1， the highest pyrolysis oil yield of 84.72 % was achieved. The increment of pyrolysis temperature promoted the occurrence of secondary reactions like Diels-Alder and aromatization reactions， generating more aromatic products. The average apparent activation energies of the two degradation stages of co-pyrolysis process were 191.05 kJ/mol and 215.22 kJ/mol. The reaction mechanisms of these two stages were aligned with order-based model and contracting volume （R3） model， respectively.

Key words: polyethylene, polyethylene terephthalate, waste plastic, co-pyrolysis, kinetics