In this paper,the 3D printing light burned magnesia-based magnesium phosphate cement material was realized by using the self-developed integrated building 3D printing equipment with mixed stirring and extrusion function. The effect of different metakaolin (MK) content on the properties of 3D printing light burned magnesia-based magnesium phosphate cement was investigated,and combined with XRD and SEM test to further analyze the influence of MK content on the hydration products and crystal appearance of light burnt magnesia-based magnesium phosphate cement. The results show that the setting time and mechanical properties of 3D printing light burnt magnesia-based magnesium phosphate cement increase first and then decrease with the increase of MK content. When MK replaces 4% to 6% of the total mass of magnesia and potassium dihydrogen phosphate,the addition of MK effectively improves the printing performance of light burnt magnesia-based magnesium phosphate cement paste. At this time,the light burned magnesia-based magnesium phosphate cement has good extrusion performance,construction performance and mechanical properties,which can meet the application requirements of 3D printing. The addition of MK does not change the crystal composition of the hydration products of light burnt magnesia-based magnesium phosphate cement,but produces a large number of amorphous amorphous hydration products,which can further fill the gap between hydration products and particles and improve the compactness of structure.