Abstract: The rapid response to industry requirements promotes the development of 3D printing technology for polyimide. However, it is quite challenging to achieve fabrication of complex polyimide parts with high dimensional accuracy and heat resistance, due to the limited types of polyimide materials and existing 3D printing techniques. To address this issue, phenylethynyl terminated polyimide oligomer (PI) with high melt fluidity was designed and synthesized. Mixing this polyimide oligomer with carbon fiber powders (CF) and nano-silica as flow agent was conducted to obtain CF/PI powders suitable for selective laser sintering (SLS) 3D printing technique. Based on the CF/PI powders, a two-step reactive 3D printing strategy was developed. SLS of self-standing sintered parts with a certain degree of crosslinking and subsequent thermal curing of resultant sintered parts with good shape retention were successfully achieved. The prepared polyimide parts give a tensile strength of 73.3 MPa, and a glass transition temperature of 376.1℃. Since CF/PI powders without small molecular weight compounds such as solvents and organic additives, are directly used as the raw material, and the main chemical reaction during the entire manufacturing process is the crosslinking of phenylethynyl groups via addition reaction without generation of volatiles, the cured polyimide parts exhibit low linear shrinkage. Furthermore, the application potential of combination of the CF/PI powders and this two-step 3D printing strategy based on SLS and thermal curing is demonstrated by successfully fabricating thin-walled and variable cross-section complex models with high dimensional accuracy.