Abstract: This research was the first time simultaneously to make unconditional and conditional QTL mapping by using single segment substitution lines for tiller number at various stages in rice. The results provided the information about “static” and “dynamic” QTLs.（1）At least 14 QTLs influenced tiller number in rice, distributing on the corresponding substitution segments of 6 chromosomes with the number of 1, 2, 3, 4, 6 and 8, respectively.（2）Both the number and the effect of tiller number QTLs were different at various stages, varying from 6 to 9 in the number and from 1.49 to 3.49 in the effect, respectively. (3) Tiller number QTLs expressedtimely, mainly arising at three stages of 0～7d, 14～21d and 35～42d after transplanting with 6 positive, 9 random and 6 negative expressing QTLs, respectively, which determined the number of the most and effective tillers.（4）Each of QTLs detected expressed at least one time or many times during the whole duration of rice.（5）The tiller number was determined by sum of QTL effects estimated by unconditional method, while the increasing or decreasing number was controlled by total of QTL effects estimated by conditional method at a given stage.（6）The effect value of a QTL at the final stage might be the sum of QTL net effects at each of all stages investigated. These results demonstrated that it is highly effective and accurate to map QTLs by using both materials of single segment substitution lines and conditional analysis methodology.