AbstractThis paper reports an electrothermal analysis of a two‐element micro flow sensor (MFS). The measurement principle is based on temperature difference between the upstream and downstream parts of electrically connected heating‐sensing elements. The two‐heater MFS, the thermal fluid flow around MFS, and the electric circuit were modeled together using a commercial general‐purpose circuit simulator based on SPICE (Simulation Program with Integrated Circuit Emphasis). The model has a partial three‐dimensional lumped thermal network model involved in a two‐dimensional one. Two‐dimensional laminar Poiseuille channel flow was assumed as the flow field in the model, and the forced convective heat transfer was calculated by energy balance at each node in the fluid flow. The tendency on the sensor characteristics was in good agreement between the simulation and experiment. © 2009 Wiley Periodicals, Inc. Electron Comm Jpn, 93(1): 58–64, 2010; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/ecj.10095