A modular support assembly for a solar power system comprising: a plurality of base units each of which includes a base frame capable of floating on a water surface and including a first tube member extending in a first direction, and a second tube member extending in a second direction transverse to the first direction and connected to said first tube member , and a plurality of solar panel supports disposed on said base frame ; and a plurality of connection units each of which interconnects said base frames of two adjacent ones of said base units , each of said connection units including a pair of sleeve members and a plurality of fasteners , each of said sleeve members having a tubular portion sleeved on one end of said second tube member of said base frame of one of said two adjacent ones of said base units , and a blind flange connected to one end of said tubular portion and closing said one end of said second tube member , wherein each of said tubular portion and said blind flange is made of a polymeric material, said blind flange having an annular peripheral portion and a plurality of annularly spaced-apart elongate holes formed in said annular peripheral portion , said annular peripheral portion projecting radially and outwardly from said one end of said tubular portion ; wherein each of said connection units further has an annular metal reinforcement piece embedded in said annular peripheral portion , said elongate holes extending through said annular peripheral portion and said annular metal reinforcement piece ; wherein said blind flanges of said sleeve members abut against each other, said elongate holes of said blind flanges are aligned with each other for passage of said fasteners , and said fasteners fasten together said blind flanges . a plurality of base units each of which includes a base frame capable of floating on a water surface and including a first tube member extending in a first direction, and a second tube member extending in a second direction transverse to the first direction and connected to said first tube member , and a plurality of solar panel supports disposed on said base frame ; and a base frame capable of floating on a water surface and including a first tube member extending in a first direction, and a second tube member extending in a second direction transverse to the first direction and connected to said first tube member , and a plurality of solar panel supports disposed on said base frame ; and a plurality of connection units each of which interconnects said base frames of two adjacent ones of said base units , each of said connection units including a pair of sleeve members and a plurality of fasteners , each of said sleeve members having a tubular portion sleeved on one end of said second tube member of said base frame of one of said two adjacent ones of said base units , and a blind flange connected to one end of said tubular portion and closing said one end of said second tube member , wherein each of said tubular portion and said blind flange is made of a polymeric material, said blind flange having an annular peripheral portion and a plurality of annularly spaced-apart elongate holes formed in said annular peripheral portion , said annular peripheral portion projecting radially and outwardly from said one end of said tubular portion ; wherein each of said connection units further has an annular metal reinforcement piece embedded in said annular peripheral portion , said elongate holes extending through said annular peripheral portion and said annular metal reinforcement piece ; wherein said blind flanges of said sleeve members abut against each other, said elongate holes of said blind flanges are aligned with each other for passage of said fasteners , and said fasteners fasten together said blind flanges . <EOS>