We identify a class of conditional entrance laws for superprocesses with dependent spatial motion (SDSM). Those entrance laws are used to characterize some conditional excursion laws. As an application of the results, we give a sample path decomposition of the SDSM and that of a related immigration superprocess. The main tool used here is the conditional log-Laplace functional technique that handles the difficulty of the loss of the multiplicative property due to the interactions in the spatial motions.