Floating mounting system is applied to solar PV power plant installation on water. Adopting HDPE material, it has passed the Hunt Water Absorption Test, Anti-Aging Test, Anti-UV Test, etc. Moreover, it can bear the pulling force that is much higher than other products. Adopting new module design in floater and main floater, it enables the array of double row in the same facing or in symmetrical facing and increases the efficiency of solar power generation and installation capacity. Moreover, it can be easily installed and saves the cost.