The use of solar photovoltaic (PV) in residential electricity generation is encouraged by Australian governments incentive. However, what extent of residents benefit from installing a grid-connected PV system is not fully understood yet. The purpose of this study is to investigate and optimize the economic, technical and environmental performance of grid-connected PV system in Queensland, Australia. Using the price of PV devices and accessories, grid electricity tariff and sale-back tariff as economic analysis inputs, and global solar irradiation as solar energy resource data, the system is simulated and optimized by HOMER software. The optimized system not only satisfies the typical residential load of 23 kWh per day but also meet the requirement of minimizing the total costs of system investment and electricity consumption during the system life (20 years). It is found that under the weather conditions of the eleven main cities of Queensland, a PV system is an effective way to reducing electricity bills and mitigating carbon dioxide emission.