Ultrasound imaging procedures are deemed as one of the most convenient and least invasive medical diagnostic imaging modalities and have been widely utilized in health care providers, which are expecting semiautomatic or fully-automatic imaging systems to reduce the current clinical workloads. This paper presents a portable and wearable soft robotic system which has been designed with the purpose of replacing the manual operation to cooperatively steer the ultrasound probe. This human-compliant soft robotic system, which is equipped with four separated parallel soft pneumatic actuators and is able to achieve movements in three directions. Vacuum suction force is introduced to attach the robot onto the intended body location. The design and fabrication of this soft robotic system are illustrated. To our knowledge, this is the first body-attached soft robot for compliant ultrasound imaging. The feasibility of the system is demonstrated through proof-of-concept experiments.