Abstract: In fluid flow field analysis, the common simulation method is 1-D simulation or 3-D simulation, In order to analyze blood fluid system more quickly and accurately and choose the appropriate sample tube at the beginning of design for the system, this paper adopts a recently emerging 1D-3D simulation method to make simulations of flow chamber subsystem. Respectively using Flowmaster and ANSYS system modeling, use MpCCI connects the two parameter coupling, realize the sheath fluid velocity of research. The software can meet the needs of design and analysis of the Hematology Analyzer fluid system. In this paper, the method of co-simulation for medical apparatus and instruments of Hematology Analyzer fluid system development provides a new method, has important significance on the subsequent simulation.