Pyrolysis process of schizochytrium-coal blends was studied by thermo-gravimetric analysis (TGA) to search the pyrolysis characteristics and interaction in the process of co-pyrolysis. The results showed that the peak width at half height of DTG curves of microalgae and coal were 225 and 68℃ respectively, and the starting temperature of devolatilization were 225 and 183℃ respectively, thus, the devolatilization of coal was slower and occurred over a wider temperature range. With the increase of the content of microalgae in blends, the release index of comprehensive characteristics of volatile D and the activity increased gradually. The interaction between microalgae and coal was related to the proportion of the sample. When the mass ratio of coal to algae was 1:1, the difference between the calculated value and the measured value of the maximum weight loss rate was 0.83%/min, which was inhibited in the process of pyrolysis. When the mass ratio of coal to algae was 3:1 or 1:3, the interaction was not obvious. The pyrolysis kinetics were investigated by Coats-Redfern integral method, and the results showed that the processes could be simplified as a first-order reaction.