Photoacoustic imaging has recently emerged as a promising imaging modality for prostate cancer, in which a light delivery method to prostate with sufficient penetrating depth and minimal invasiveness is required in the photoacoustic imaging technique for examining prostate. In this letter, we developed a prostate photoacoustic imaging system by using transurethral light delivery approach utilizing a mirrorbased sidefiring fiber(MBSFF),and a transrectal focused transducer for scanning the photoacoustic signals. Results of phantom experiments demonstrate the feasibility of the proposed method. The sidefiring fiber would be more advantageous if a priori knowledge of cancer locations require additional confirmation. And through rotating the fiber, a full visualization of all targets within the field surrounding the urethra can be obtained. The approach can play a significant role for the  optimization of transurethral light delivery to prostate.