This research is aimed to establish the small wireless sensor network under the real environment. The objectives this research is aimed to study the data transmission and evaluate the data transmission performance of RPL protocol in wireless sensor network. Four nodes of wireless sensor network have been installation and transmissions between nodes in single-hop and multi-hop have been simulation for testing and analyzing data from the network following the transmission performance index. The research found that the number of hop and building environment are the principle factor to the performance of RPL protocol this might be the major limit to implement the RPL protocol in wireless sensor network