This study aims to investigate the apparent backscatter of cancellous bone from the second ultrasonic harmonics using an imaging system. A cylinder model was used as the bone trabecular model and a positive correlation was found between the power spectrum of the second harmonics and trabecular thickness. The result of the in vitro experiment using ultrasound imaging system shows that the apparent backscatter parameters from the second harmonics (R=0.53- 0.71) correlates better with bone density than the fundamental backscatter signal (R=0.39-0.47).