In order to meet the requirements for hitting a target at a specified attack angle while intercepting high-speed maneuvering targets, a three-dimensional multivariable super-twisting fixed-time sliding mode interception guidance law with constraint of attack angle is proposed.Based on the three-dimensional relative motion model of the missile and the target, the interception guidance problem is transformed into a second-order system control problem about line-of-sight angle.Based on the terminal sliding mode control theory and the multivariable super-twisting algorithm, the multivariable terminal sliding mode surface and the interception guidance law with constraint of attack angle are designed respectively.Lyapunov function is used to prove the fixed-time stability of closed-loop guidance system.Simulation comparisons with the non-singular terminal sliding mode interception guidance law show that the proposed interception guidance law has good interception accuracy and robustness.