Abstract: Saturated core fault current limiter needs an additional air core reactor to improve current limiting performance, resulting in large volume and floor area. Therefore, a compact saturated core fault current limiter (CSFCL) based on non-orthogonal decoupling principle is proposed in this paper, which has the advantages of small floor area, small volume and good current limiting performance. Firstly, the principle of non-orthogonal decoupling is introduced. Combined with the traditional hybrid-biased saturated core fault current limiter (HSFCL), the topology of fault current limiter integrating non-orthogonal decoupling windings is proposed. Its equivalent magnetic circuit and electrical circuit are established to explain the principle of CSFCL. Secondly, a calculation method of multi-stage decoupling winding inductance with air gap is proposed, which improves the accuracy by 35% compared with the traditional method. Then, the response time and current limiting ratio of fault current limiter are designed and calculated. 220 kV CSFCL and HSFCL finite element simulation are carried out to verify the theoretical analysis. Finally, a small capacity fault current limiter prototype is manufactured and the experimental research is carried out. Compared with HSFCL, the overall volume of CSFCL is reduced by 47.8% and the floor area is reduced by 85.1%. The simulation and experimental results verify the effectiveness of the topology.