Tumors of the urinary system include those in the urinary and reproductive systems, of which tumors of the prostate, bladder, and kidney have the highest incidence. In recent years, due to changes in dietary structure, prostate cancer has become the most common type of male genitourinary system cancer. Furthermore, due to tobacco consumption, increases in industrialization, and the age of the population, the incidence of bladder cancer in both males and females in both urban and rural areas, has shown an increasing trend. The incidence and mortality of kidney cancer have also increased and negatively affected the lives and health of all residents. While surgery, radiotherapy, and chemotherapy have greatly improved the cure and survival rates of patients with urinary tumors, we lack methods for early detection and effective long-term treatment. New tools and methods for diagnosis and treatment are thus urgently needed. Recently, CRISPR/Cas9 has become an efficient method to alter the genome in many organisms. It can be used to activate or inhibit gene expression, which greatly facilitates the editing of targeted genes, both in vivo and in vitro. It provides a powerful scientific research tool to analyze the mechanisms of disease occurrence and development and to develop advanced targeted drug delivery. The diagnosis and treatment of human tumors will consequently be improved as this technology will surely accelerate cancer research. In this article, we discuss how CRISPR/Cas9 technology can be used to research and treat genitourinary system tumors will consequently be improved as this technology will surely accelerate cancer research. Here, we review the current applications of CRISPR/Cas9 technology for genitourinary system tumor research and therapy.