In this study, a pretreatment on aluminum oxide substrate by sputtering with an aluminum oxide film is investigated to improve the surface roughness of a deposited NiCrSi (55/40/5) thin film resistor. Effect of sputtering parameters and thermal treatment on the deposited aluminum oxide film on aluminum oxide substrate are studied. Aluminum oxide thin film with Ar/O-2 flow rate of (55/5) sccm shows the lowest surface energy at 41.5 J/m(2) that would be helpful in improving the quality of the deposited resistive NiCrSi thin film. On the other hand, with increasing the thickness of aluminum oxide film, the surface roughness of the alumina substrate is observed to be significantly decreased and is quite helpful in improving the continuity of deposited resistive NiCrSi film. According to our investigations, developing a narrow distribution of high resistance thin film resistor by reducing the thickness of NiCrSi film is feasible when the aluminum oxide substrate was pretreated by sputtering aluminum oxide film and the continuity of NiCrSi thin film can be significantly improved, leading to a narrow resistance distribution of thin film resistor.