As infrastructures are being deteriorated, nondestructive evaluation of existing structures and construction quality control are increasingly demanded in the construction industry. The importance of predicting compressive strength of concrete structure is also gradually increasing in construction industry. The estimation of concrete compressive strength is a critical factor of the construction management and quality control. This study has been conducted using Ultrasonic pulse velocity method and Rebound hardness method, which are nondestructive test methods for the estimation of the concrete compressive strength. The method for predicting the strength and the position of rebars of reinforced concrete slabs and detecting void of reinforced concrete slab are derived from the relationship between compressive strength and stress wave velocity. It is focusing to examine the relationship among compressive strength of concrete, Ultrasonic pulse velocity method and result by rebound number by Schmidt hammer test.