In this paper, we propose a novel interval type-2 fuzzy logic controller (IT2FLC) for interval system. The precise mathematical model of the controlled plant is not required to design this IT2FLC. Design procedure of the IT2FLC is explored in detail. A typical linear interval system with 50% parameter variations is adopted to demonstrate the effectiveness of the proposed IT2FLC. For better understanding the performance of IT2FLC, numerous shapes of membership functions and variation of rule numbers of rule table are evaluated for simulation thoroughly. The simulation results are compared with those from type-1 fuzzy logic controller (T1FLC) under same conditions. It shows that the performance of IT2FLC is much better than that of T1FLC if the number of rule is reduced.