a low temperature solar rankine system utilization R245fa as the working fluid is proposed and an experimental system is designed constructed and test . Both the evacuated solar collectors and the flat plate solar collector are used in the experimental system meanwhile a rolling R-245fa expander is also mounted in the system the new designed R245fa expander works stably in the experiment while an average expansion power output of 1.73kw and an average isentropic efficiency of 45.2 % the overall power generation lector it is about 3.2% the experiment results show that using r245fa as working flud in the low temperature solar power rankine cycle system is feasible and the performance is acceptable