Due to the low efficiency and frosting of the air source heat pump (ASHP) in extreme cold climates, the use of existing solar water heaters or dedicated solar collectors as auxiliary heat sources can further improve the overall operating efficiency of ASHPs. Based on the case study of a typical rural building in Shandong, the simulation models of the solar-air source heat pump (SASHP) systems connected respectively in series and in parallel have been established under the TRNSYS platform. The operating performance and the solar fraction of the two systems have been simulated under different conditions. The results show that the performance of the parallel SASHP system is higher than that of the series SASHP system. The research results can provide certain guideline for the clean heating in rural areas of Shandong province in China.