Taking thermal parameters such as evaporating temperature, condensing temperature, superheating temperature and sub-cooled temperature as the basic variables and serving COP and heating capacity as evaluating indicators, this paper builds a series of mathematical models according to the rationale of WSHP and the correlation of its components and a simulation platform based on Laboratory Virtual Instrument Engineering Workbench (LabVIEW), simulates and analyzes the influence of thermal parameters on the performance of WSHP under variable working condition. The results show that evaporating temperature and condensing temperature have more significant effect on the performance of WSHP than both of superheating temperature and sub-cooled temperature and lower condensing temperature and higher evaporating temperature can raise the value of COP but reduce heating capacity. They also show that lower superheating temperature will bring higher value of COP but lower heating capacity and higher sub-cooled temperature can make both COP value and heating capacity increase. On the simulative condition, the influence rates of evaporating temperature, condensing temperature, superheating temperature and sub-cooled temperature relative to COP of WSHP respectively are 2.25%，2.61%，0.7% and 0.51% and the influence rates of these temperatures relative to heating capacity respectively are 1.32%，1.09%，0.58% and 0.77%. These results may provide with some reliable foundations on optimizing operation and control of WSHP under variable working condition.