For thermomechanical fabrication of the micro/nano structure, a micro-heater made of Al doped poly-Si was fabricated. The Al doped poly-Si film was prepared by annealing from Al/a-Si∶H compound film under 750 K for 18 h on a Si3N4 substrate using Aluminium Induced Crystallization (AIC) process, and the characteristics of the transformation caused by annealing were analyzed by Raman scattering spectroscopy, scanning electron microscopy and a resistivity meter. It was shown that the boundary between an Al layer and an a-Si∶H layer disappears after annealing,and a uniform film is formed. After annealing，the Raman spectral peak shifts from 478 cm-1 to 520 cm-1,which means the film surface changes from the a-Si∶H to the highly-crystallized poly-Si. Meanwhile, the resistivity of the film declined is from over 1010Ω·cm to 16.8×10-3 Ω·cm at 300 K for doping of Al atoms. The results indicate that the bilayer film (Al/a-Si∶H) has been changed into a uniform Al doped highly-crystallized ploy-Si film. Furthermore,the integration of the Al doped poly-Si micro-heater and Si3N4 cantilever was also discussed. Simulated by ANSYS, the micro-heater is heated to 782.8 K under a periodic electrical pulse with a voltage of 10 V and duration of 0.3 μs. When the pulse disappears, its temperature cools down to 420 K within 1 μs. The simulation results show that the Al doped poly-Si micro-heater has good thermoelectric properties, and it is well suitable for the thermomechanical micro/nano structure fabrication.