The sensor nodes of wireless sensor networks (WSNs)-based agricultural monitoring system are required to collect the environmental data periodically, including temperature and humidity, and additionally anytime monitoring shall be required to be realised among the monitored area with minimised quantity of sensor nodes. To meet the mentioned goal, a solar power-moving schedule of mobile-based optimal coverage (SPMSC) is proposed. In accordance with the content of SPMSC, every sensor node is able to obtain energy through the solar panel. The moving schedule of sensor nodes is determined through predicting the quantity of solar power as to realise the optimal coverage project with the minimised quantity of sensor nodes and the energy consumption. As the simulation result indicates, the proposed SPMSC, compared with other similar projects, has the 4% decrease of sensor node quantity and the 10% increase of the network lifetime.