In this paper, one class of distributed fixed-time cooperative control scheme is proposed for parallel DC-DC converter systems with super-capacitor loads in order to achieve a current-sharing objective in a fixed time. The communication network between parallel-connected sub-systems is depicted as a undirected graph. With the aid of the input output feedback linearziation technique, the difficult fixed-time current-sharing control design is converted into the consensus tracking problem of first-order multi-agent systems in a fixed horizon. Based on the nearest neighborhood rule, the fixed-time current-sharing cooperative control law with tuneable gains is designed by adopting the sign function, the Lapalican matrix and the pining gain matrix. The closed-loop system stability is rigorously proved using the Lyapunov function and the upper bound of the convergence time is derived accordingly. The proposed fixed-time current-sharing method can overcome the strong dependence on initial system states compared with the finite time control method, which can also improve the system convergence performance. The effectiveness and applicability are verified by simulations.