Robot-assisted laparoscopic radical prostatectomy is a common treatment for prostate cancer. Traditional rigid instruments, on the other hand, have operating blind areas and lack real-time position and shape feedback, which may result in additional trauma during the surgery. To this end, this work describes the development of a soft robot for single-port transvesical radical prostatectomy (STRP) using a multicore fiber with Fiber Bragg Gratings (FBGs). The shape sensing method is proposed in the meanwhile to rebuild the soft robot's shape from the wavelength data of FBGs. The experiments are carried out to confirm that the suggested strategy is workable.