There is significant effect on thermal behaviors pyrolytic characteristics of the interactions between microalgal components. In order to understand the reaction process, interaction mechanism, and better utilization of microalgae, co-pyrolysis of microalgal model compounds (soybean protein (PT), sunflower oil (OL) and sucrose (SC)) was carried out with TG-FTIR and Py-GC/MS. The results showed that co-pyrolysis of PT and SC significantly changed the thermal behaviors, and accelerated decomposition at lower temperature to generate CO, CO2 largely. And it could promote the generation of linear O-compounds (such as acetic acid), and inhibit the formation of N-heterocycles and furans. Moreover, OL co-pyrolysis with PT or SC could significantly promote the formation of long-chain acid and inhibit the generation of aliphatics. Meanwhile, co-pyrolysis of PT and OL inhibited the generation of N-heterocycles. And co-pyrolysis of SC and OL accelerated the generation of furans. Furthermore, co-pyrolysis of model compounds reduced the average activation energy of the pyrolysis process, and changed the reaction kinetic model.