The green macroalga Enteromorpha clathrata was pyrolyzed with or without catalysts at the temperature of 550 degrees C for producing high-quality bio-oil. The ZSM-5 and 1,2,3 mmol Mg-Ce/ZSM-5 catalysts were introduced to investigate the yields and components distribution of bio-oil. Increase of bio-oil production was obtained with the use of ZSM-5 and 1,2,3 mmol Mg-Ce/ZSM-5 catalysts. The 1 mmol Mg-Ce/ZSM-5 catalyst exhibited more promising property for promoting the relative content of C5-C7 compounds, and decreasing the relative content of acids in bio-oil. The results suggested that E. clathrata had potential as pyrolysis feedstocks for producing the high-quality bio-oil with large amounts of C5-C7 compounds and low relative content of acids when the 1 mmol Mg-Ce/ZSM-5 catalyst was used. Furthermore, the physicochemical properties of ZSM-5 and 1 mmol MgCe/ZSM-5 catalysts were investigated by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and temperature-programmed desorption of ammonia.