Background. RhoJ, an endothelially expressed member of Cdc42 (cell division cycle 42) subfamily of Rho GTPase, plays an important role in endocytic pathway, adipocyte differentiation, endothelial motility, tube formation, and focal adhesion. RhoJ is a selective and effective therapeutic target in tumor tissues or retinopathy. Methods. A systematic review was related to "small Rho GTPase" or "RhoJ" with "endothelial motility, tube formation and focal adhesion" and "tumor therapy". This led to many cross-references involving RhoJ and these data have been incorporated into the following study. Results. We have grouped the role of RhoJ according to three main effects: RhoJ regulates endocytic pathway and adipocyte differentiation in early studies, and RhoJ shows an important role in endothelial cell biology; furthermore, RhoJ blockade serves as a target in tumor vasculature and enhances the effects of anticancer drug. Conclusions. More research is necessary to understand the role of RhoJ in many aspects, on the basis of current knowledge of the role of RhoJ blockade in tumor vessels, there are opportunities for the therapy of tumor, and RhoJ is expressed outside tumour vasculature and is involved in wound healing. Taking advantage of the opportunities could result in a development in tumor therapy.