Laser solid forming (LSF) TC4 alloys and forging TC4 titanium alloy are studied. LSF-TC4 alloys are processed by different heat treatments to get different heat treatment microstructures. In order to figure out the relationship between ultrasonic parameters and microstructures, ultrasonic nondestructive testing is taken on these alloys to get ultrasonic longitudinal wave velocity and attenuation coefficient. The results show that samples with different microstructures have different velocities and attenuation coefficients. Compared with longitudinal wave velocity, attenuation coefficient is more sensitive to the change of microstructure of laser solid forming alloys.