Objective To investigate the influence of fishbone diagram in the incidence of blood residual after sealing tube indwelling needle in cardiovascular disease patients.Methods Two hundred and ninety-three patients(1,035 times)with sealing tube intravenous indwelling needle were assigned into control group and another 272 ones(1,276 times)with the needle into experiment group according to admission sequence. In the former group the method of conventionally sealing the tube for intravenous indwelling needle was applied and in the latter,fishbone diagram was applied to analyze the key factors for blood residuals and regulate pertinent measures for effective sealing of tube.The two groups were compared in terms of incidence of blood residuals.Result The incidence of blood residuals in the experiment group was significantly lower than that in the control group(P<0.05).Conclusion The fishbone diagram is effective in reducing the incidence of blood residuals after sealing the tube for intravenous indwelling needle by way of taking effective interventional measures after screening out the key influential factors for blood residuals.