The stability of the structures to be built on the soil depends on the geo material at which it rests. Expansive soil is characterized by its high swelling behavior, consecutive volume change and loses of strength in CBR when saturated. In order to improve the geotechnical parameters of expansive clay to meet technical specifications in the construction industry, studying of expansive soil stabilization is more emphasized. This research work is aimed to evaluate the suitability of locally produced eucalyptus tree wood ash for stabilization in combination with hydrated lime on the engineering properties of expansive soil. The laboratory work involved grain size analysis and index property determination to classify soil sample. In order to evaluate the soil samples engineering properties Compaction test, California Bearing Ratio tests, unconfined compressive test, free swell and shrinkage limit tests were conducted. After determining the natural property of the soil sample, locally produced eucalyptus tree wood ash was added to expansive soil sample in multiples of two percentages from 2% to 12% and tests were conducted. Lime percentages of 1,3,5&7 were added in expansive soils to study its impact. To assess the combined effect of wood ash and hydrated lime mixture as a stabilizer previously listed percentages of wood ash and lime ratios combined together and test results were evaluated. From the laboratory test results and analysis it was confirmed that locally produced eucalyptus wood ash can improve the engineering property of expansive soils to some extent but the mixture of hydrated lime and wood ash is more effective in enhancing the property of expansive soil by reducing cost of stabilizers and environmental pollution.