The present invention disclosed a portable scoliosis assessment device to quantitatively measure shoulder height difference (SHD) and angle of trunk rotation (ATR) of scoliosis patients. The portable scoliosis assessment device comprising a device casing two device casing stands and respectively; two extension racks and respectively; an accelerometer a microcontroller, a rotary encoder, an I2C Serial Adapter, a LCD Display Module, a LED Bulb, a battery, a power button, a measurement mode conversion button and a gear. The portable scoliosis assessment device (10) is helpful for the doctors to detect scoliosis in patients and monitor the progressive of the scoliosis patients before and after corrective surgery.