NOVELTY - Producing solar energy water tank, comprises (i) producing an inner shell; (ii) producing an outer shell; (iii) assembling inner and outer shells; (iv) preparing heat storage material by (a) producing a mixing drum, (b) pouring raw materials including e.g. silica, alumina, calcium oxide, magnesium oxide, potassium oxide, sodium oxide, ferric oxide, cupric oxide, fly ash, closed-cell expanded perlite beads and barium hydroxide, (c) stirring the substances, (d) choosing plate-type balling machine, and (e) drying; and (v) loading heat storage material to shell body and between inner shell.    USE - The method is useful for producing solar energy water tank (claimed).    ADVANTAGE - The method solves complicated maneuver, and other technical issues of water tank production process; has simple preparation, and operation procedures; and produces product having long-lasting heat storage property.    DETAILED DESCRIPTION - Producing solar energy water tank, comprises (i) producing an inner shell by welding, and molding 6 rectangular blocks made of stainless steel plate, and wielding inner shell and an upper shell with a water inlet tube and a water outlet tube, and welding the outer side wall of the shell fixed with an upper splice block, where the splice block is set with a splice groove; (ii) producing an outer shell by taking 6 rectangular blocks made of stainless steel plate, and welding, and molding 5 blocks of stainless steel plate, and temporarily welding the last stainless steel plate, welding the steel plate with a connecting pipe set on inner wall at outer side of the shell body which is set with a water inlet pipe used for penetrating through a hole A and water outlet pipe which passes through hole B; (iii) assembling inner and outer shells by mounting the inner shell into the shell body, so that the inlet and outlets of the shell body are respectively provided with a hole A and a hole B, mounting the other end of a mounting tube which is inserted with splice slot, and welding the upper part of the stainless steel plate, and welding the gap between the inlet and outlet pipelines with hole A and hole B, and sealing the inlet, and outlet pipelines with the shell body, then welding the outer shell into a tube by using a heat storage material, and fitting the valve in the heat storage material into the outer end of the tube; (iv) preparing heat storage material by (a) producing a mixing drum by taking mixing drum of volume 10-50 l, where the mixing drum is provided with a stirring shaft and a stirring blade, and the stirring shaft is driven by a motor, and the stirring blades are fixed to the stirring shaft, (b) pouring raw materials including 20-30 wt.% silica, 3.9-7.9 wt.% alumina, 0.4-1.2 wt.% calcium oxide, 0.6-1.2 wt.% magnesium oxide, 0.6-1.2 wt.% potassium oxide, 1.2-1.8 wt.% sodium oxide, 0.2-0.4 wt.% ferric oxide, 1.8-2 wt.% cupric oxide, 1.8-5 wt.% cement, 2.5-5 wt.% fly ash, 1.5-2 wt.% closed-cell expanded perlite beads, 0.5-0.8 wt.% barium hydroxide, 0.2-0.5 wt.% carboxymethyl starch, 5.5-6.8 wt.% sodium acetate trihydrate, 0.1-0.2 wt.% carboxymethyl cellulose, 0.1-0.2 wt% magnesium chloride hexahydrate, 0.1-0.2 wt.% sodium carboxymethyl cellulose and water (balance amount), successively into the mixing bucket, (c) uniformly stirring the substance added into stirring shaft using stirring blade for 0.5-2 hours, (d) choosing plate-type balling machine, and stirring the material poured into the plate-type balling machine, to obtain small balls having diameter of 1-3 cm, and (e) drying the materials using a drier, to obtain pellets, and obtaining solar water tank based on requirements; and (v) opening valve, loading heat storage material into shell body and between inner shell, and then closing the valve.