Casting method of sand mold of long and thin cast iron bar

The invention provides a casting method of a sand mold of a long and thin cast iron bar. The casting method of the sand mold of the long and thin cast iron bar comprises the steps that a core box is made according to the size of the cast iron bar in a design drawing, wherein bar-shaped molds are arranged inside the core box in an inclined mode; crude sand, furan resin and curing agents are mixed and stirred, and then are put into the core box; after curing treatment is accomplished, the bar-shaped molds are drawn out of the core box, so that a sand core with a plurality of mold holes is formed; the dried sand core and wood blocks which are arranged on the two sides of the sand core and can block hole openings of all the mold holes are put into a sand box together, and the wood blocks are taken out after a mixture is solidified; molten iron flows through the mold holes from a pouring-in cavity and arrives at an overflowing cavity which is formed in the low hole openings of the mold holes, and pouring is accomp