Soil stabilization is a method to improve soil properties either by mechanical means or by adding another material to the soil with the purpose is to increase the strength or bearing capacity of the subgrade to the construction built on it. Subgrade with low bearing capacity can cause damage or collapse of construction above it. In this study, the type of stabilized soil is clay. Repairing this subgrade by adding addictive material to the clay using palm shell ash and asphalt emulsion with 8% of palm shell ash content as a dependent variable and emulsion asphalt of 3%, 6%, 9%, and 12% as an independent variable. The purpose of this step is to get the optimum mixture content as a stabilizing agent. Based on testing, the optimum mixture content is 8% palm shell ash+9% emulsion asphalt. The addition of this addictive material can reduce water content by 13.23%, plastic index by 74.47%, and shrinkage by 43.75% during the 14 days curing period, and increase the bearing capacity of subgrade through CBR testing of unsoaked and soaked respectively each of 114.15% during the curing period of 14 days and 211.1% during soaking of 4 days after curing period of 14 days. Based on the result of testing, this addictive material can be used as a stabilizing material.