The cathode current density and the fluid field relevant to the growth of electroforming layer is studied with numerical analysis to explore the inherent laws of micro-electroforming that is a key technology of UV-LIGA. By taking the crossing electroforming layer of a micro-fluidic chip mold as a research object,a mathematical model is established. Then,the current density and the fluid field are described with partial differential equations,and the 3D numerical simulation of the micro-electroforming system is performed with the finite element method to obtain the simulated results of the current density distribution and fluid field distribution. Choosing measuring points on the crossing electroforming layer,the simulated growth height during 4 hour electroforming is calculated based on the simulated data of current density and fluid velocities at the measuring points. Finally,the simulated growth height of electroforming layer is compared with that gotten from the micro-electroforming experiment under the same technological condition. The results indicate that the simulated one of electroforming layer is close to the experimental growth height to every measuring point and show low absolute deviations in a maximum of 4.437 μm and a minimum of 0.264 μm. These results also indicate that the numerical simulation can be used in the analysis and design of micro-electroforming,and can reduce the developing time of micro-electroforming technology.