The invention relates to an ultrasonic system and a method for optimizing gray level value of ultrasonic images used in the ultrasonic system, the method comprises: an acquiring step for acquiring the ultrasonic image a searching step for searching non-evenly divided sub-areas from the acquired ultrasonic image analyzing step for analyzing the change of gray level in each of the sub-areas in the direction of depth and calculating step for calculating an optimized gray level value of the ultrasonic image based on the result of the analyzing step. By implementing the method of present invention, a better image equilibrium effect is obtained in the ultrasonic system.
