The invention discloses a fore shaft steel pipe pile cofferdam and a construction method thereof, and relates to the field of bridge engineering. The cofferdam comprises a plurality of fore shaft steel pipe piles connected sequentially and closely. Inner supports are arranged in a foundation pit defined by the multiple fore shaft steel pipe piles. A bored pile is arranged in the cofferdam. The cofferdam further comprises concrete sand cushions. The concrete sand cushions are arranged between the inner supports and the fore shaft steel pipe piles. The method comprises the following steps that the inner supports are assembled, and the inner supports needing to be lowered are fixed to a hoisting system; the inner supports needing to be lowered are lowered to a design position through the hoisting system; and the concrete sand cushions are constructed between the fore shaft steel pipe piles and the inner supports. The concrete sand cushions are arranged between the fore shaft steel pipe piles and the inner supports, the bearing capacity between the fore shaft steel pipe piles and the inner supports is improved, construction is convenient, and the construction efficiency is high.