The probability that the starting points or ending points of time intervals of two random events are equal is zero. Hence, in order to improve the efficiency of temporal reasoning, We introduced Heisenberg’s uncertainty principle to delete the fifteen basic temporal relations that the probabilities they happen were zero from INDU temporal system. The other ten basic temporal relations that the probabilities they happen were greater than zero were reserved. We used the characteristic sets to represent the ten basic temporal relations and got a fuzzy temporal system--UINDU. We gave the composition table of UINDU. It simplified INDU greatly. The experiments showed that the efficiency of UINDU was better than INDU.