Cloud computing is a novel parallel platform, this paper proposed a kind of simple parallel genetic algorithm (PGA) using Cloud computing called SMRPGA. Comparing with the traditional PGAs using high performance computers (HPC), cluster or Grid, SMRPGA is simple and easy to be implemented. Another advantage is that PGA using Cloud computing is easy to be extend to larger-scale, which is very useful for solving the time-consuming problems. A prototype is implemented based on Hadoop, which is an open source Cloud computing. The result of running two benchmark functions showed that the speed-up of PGA using Cloud Computing is not obvious considering the long communication time and it is suitable to solve the time-consuming problems.