The information era puts higher requirements on current students’ learning methods to develop 21st-century skills. Project-based learning (PBL) and gamified learning have been two effective learning approaches, leading to an innovative exploration of combining both to improve learning outcomes. This study presents a systematic review of the literature published on “gamified PBL” (GPBL) over the past six years, focusing on GPBL approaches, learning outcomes, technical tools and theories. The results show that the gamified approaches of project-based learning can be divided into four types: gamify structure and procedure of PBL, gamify content of PBL, integrate prefabricated educational/serious games in PBL, and make a game as the activity of PBL. Most of the studies affirmed the positive effects of GPBL in enhancing students’ learning outcomes, especially for learning experience and motivation. Adopted techniques and theories in the reviewed studies were also summarized. In conclusion, we acquired four findings based on the discussion: the characteristics of GPBL are diverse; design-based learning are an innovative and creative method used in GPBL; studies of GPBL emphasized collection and description of the whole-process data; technical issues should be paid great attention to. In addition, a number of suggestions for future research are provided in this review.