Abstract: To study grass carps (Ctenopharyngodon idellus) conveyance performance and injuries factors of jet fish pumps (JFP), a JFP with throat diameter of 60 mm was designed and evaluated by high-speed video observation as well as computational fluid dynamics (CFD). The results show that the peak conveyance capacity of JFP can reach 918 kg·h^-1 at lift height of 2.24 m with input power of 2.83 kW. No test fish died or with viscera damage after conveyance but part of descaling was found occasionally, which was mainly caused by the shear layer in JFP. Further tests reveal that, after passing the JFP, respiratory rate and some blood indices of the test fish changed but all of them elementarily recovered within 24 h. It should be noted that collision injury might be caused by the deflection of inner flow. The rapid change of pressure may also affect the test fish. However, due to the short passing time in JFP, none of the above factors killed the test fish.