Transient thrombocytopenia is a common hematologic disease occurring after liver transplantation. If left untreated, thrombocytopenia after transplant can lead to the rejection of graft and mortality. Therefore, the evaluation and prevention of sustained thrombocytopenia after liver transplantation can help intercept the resultant side effects. Color Doppler ultrasound images are usually combined with grayscale images to display duplex ultrasonography images. In so doing, they provide the simultaneous visualization of the anatomy of the region. Concomitant perfusion changes in the liver parenchyma can be distinguished using color Doppler ultrasound, with a sensitivity, specificity, and accuracy of 91%, 97%, and 95%, respectively; accordingly, the false-positive rate will be lowered. Therefore, the use of this method for the detection of hepatic arterial peak systolic velocity, hepatic arterial resistance index, and hepatic arterial diameter before, during, and after transplantation can be of great help to the prognosis of thrombocytopenia, and therapy should be taken. As evidenced by the obtained results, the use of color Doppler ultrasound alone is not enough to diagnose thrombocytopenia. Nonetheless, along with other diagnostic methods, it can be a useful method for the early diagnosis of these patients after liver transplantation