Data broadcast is an advanced technique to realize large scalability and bandwidth utilization in a mobile computing environment. In the heterogeneous data broadcast, the data size is variant with time in multiple broadcast channels. However, traditional indexing schemes do not consider variant data size to design indexing techniques in the multiple channels. Therefore, the above drawback leads to large power consumption in the heterogeneous data broadcast. In this paper, we remedy the problem of devising an indexing technique to index the data of variant size via the multiple channels. In view of the characteristics of variant data size in the multiple channels, we propose an indexing technique using an index tree to minimize average waiting time and average tuning time. Experimental results show that our approach is able to generate broadcast programs including data indices with high quality and is very efficient in the heterogeneous data broadcast.